Chapter 10 c. There are 10 possible results. Chapter 10 Opener Out of 20 spins, you think you will spin a 4 two times. Check students’ work with tallies in a table and closeness of their guess. Try It Yourself (p. 399) 1. Baseballs 2 1 = = Footballs 6 3 So, the ratio of baseballs to footballs is 2. 2. a. an even number; Spinning an even number has 5 possible results: 2, 4, 6, 8, or 10. Spinning a multiple of 4 has only 2 possible results: 4 or 8. 1 . 3 b. neither; Spinning an even number has 5 possible results: 2, 4, 6, 8, or 10. Spinning an odd number has 5 possible results: 1, 3, 5, 7, or 9. Footballs 6 3 = = Total pieces of equipment 8 4 So, the ratio of footballs to total pieces of equipment 3 is . 4 3. a. Answer should include, but is not limited to: Students will work in pairs to play Rock Paper Scissors 30 times and record the results in a table. b. There are 9 possible outcomes because there are Sneakers 2 1 3. = = Ballet slippers 4 2 9 results possible in the table. Player A c. Player B 1 So, the ratio of sneakers to ballet slippers is . 2 Sneakers 2 1 4. = = Total number of shoes 6 3 So, the ratio of sneakers to total number of shoes is 5. 1 . 3 green beads 3 1 = = blue beads 6 2 1 The ratio of green beads to blue beads is . 2 6. red beads 4 = green beads 3 4 The ratio of red beads to green beads is . 3 7. Section 10.1 Out of 20 spins, you think you will spin orange 4 times. Check students’ work with tallies in a table and closeness of their guess. Copyright © Big Ideas Learning, LLC All rights reserved. Rock Tie A wins B wins Paper B wins Tie A wins Scissors A wins B wins Tie because there are three ways for each player to win. 4. Make a list or table that shows all possible results. 10.1 On Your Own (p. 403) 1. a. The possible outcomes are choosing A, B, C, D, E, F, G, H, I, J, and K. b. consonants vowels B, C, D, F, G, H, J, K A, E, I The favorable outcomes of choosing a vowel are choosing A, E, and I. 2. a. There are 8 marbles. So, there are 8 possible outcomes. b. 1. a. There are 2 possible results. b. There are 5 possible results. Scissors d. no; Each player has an equal chance of winning 10.1 Activity (pp. 400 –401) Out of 20 flips, you think you will flip heads 10 times. Check students’ work with tallies in a table and closeness of their guess. Paper There are three ways Player A can win, three ways Player B can win, and three ways the players can tie. green beads 3 1 = = total beads 15 5 The ratio of green beads to the total number of beads 1 is . 5 Rock blue not blue blue, blue green, red, purple, yellow, yellow, yellow There are 2 blue marbles. So, choosing blue can occur in 2 ways. c. yellow not yellow yellow, yellow, yellow blue, blue, green, red, purple There are 5 marbles that are not yellow. So, choosing not yellow can occur in 5 ways. The favorable outcomes of choosing not yellow are blue, blue, green, red, and purple. Big Ideas Math Red Accelerated Worked-Out Solutions 285 Chapter 10 11. 10.1 Exercises (pp. 404 –405) divisible by 3 not divisible by 3 3, 6, 9 1, 2, 4, 5, 7, 8 Vocabulary and Concept Check 1. Rolling an even number on a number cube is an event The favorable outcomes of choosing a number divisible by 3 are choosing 3, 6, and 9. because it is a collection of several outcomes. 2. Sample answer: An outcome is any of the possible results of an experiment, while a favorable outcome is an outcome of a specific event of the experiment. 12. a. There are 2 blue marbles. So, choosing blue can occur in 2 ways. b. The favorable outcomes of the event are blue and blue. Practice and Problem Solving 3. Because the spinner has 8 different numbers, there are 13. a. There is 1 green marble. So, choosing green can occur in 1 way. 8 possible outcomes. b. The favorable outcome of the event is green. 4. even odd 2, 4, 6, 8 1, 3, 5, 7 14. a. There are 2 purple marbles. So, choosing purple can occur in 2 ways. b. The favorable outcomes of the event are purple and There are 4 ways to spin an even number and 4 ways to spin an odd number. purple. 15. a. There is 1 yellow marble. So, choosing yellow can occur in 1 way. 5. The possible outcomes are choosing 1, 2, 3, 4, 5, 6, 7, 8, and 9. 6. b. The favorable outcome of the event is yellow. 16. a. 6 not 6 6 1, 2, 3, 4, 5, 7, 8, 9 The favorable outcome is choosing a 6. 7. odd not odd 1, 3, 5, 7, 9 2, 4, 6, 8 not red red, red, red green, blue, blue, purple, purple, yellow There are 6 marbles that are not red. So, choosing not red can occur in 6 ways. b. The favorable outcomes of the event are green, blue, blue, purple, purple, and yellow. The favorable outcomes of choosing an odd number are choosing 1, 3, 5, 7, and 9. 8. red greater than 5 not greater than 5 6, 7, 8, 9 1, 2, 3, 4, 5 17. a. blue not blue blue, blue green, red, red, red, purple, purple, yellow There are 7 marbles that are not blue. So, choosing not blue can occur in 7 ways. The favorable outcomes of choosing a number greater than 5 are choosing 6, 7, 8, and 9. b. The favorable outcomes of the event are green, red, red, red, purple, purple, and yellow. 9. odd number less than 5 not an odd number less than 5 1, 3 2, 4, 5, 6, 7, 8, 9 The favorable outcomes of choosing an odd number less than 5 are choosing 1 and 3. 10. less than 3 not less than 3 1, 2 3, 4, 5, 6, 7, 8, 9 The favorable outcomes of choosing a number less than 3 are choosing 1 and 2. 18. There are 7 marbles that are not purple, even though there are only 4 colors. Choosing not purple could be red, red, red, blue, blue, green, or yellow. 19. Presidential not Presidential Presidential, Presidential, Presidential Susan B. Anthony, Susan B. Anthony, Susan B Anthony, Susan B. Anthony, Susan B. Anthony, Kennedy, Kennedy There are 7 coins that are not Presidential Dollars. So, choosing not a Presidential Dollar can occur in 7 ways. 20. false; Spinning blue and spinning red have the same number of favorable outcomes on Spinner A. 286 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 21. true; There are three blue sections and two green sections. Section 10.2 22. false; There are five possible outcomes when spinning 10.2 Activity (pp. 406 –407) Spinner A. 1. a. Answer should include, but is not limited to: Students will write rules for a game that uses the given spinner. The rules should be written so players can clearly understand the object of the game. 23. true; There are four red sections. 24. false; Spinning not green can occur in eight ways on Spinner B. b. Answer should include, but is not limited to: After playing the game and analyzing the outcome, students will determine if they should revise the rules that they wrote for the game in part (a). 25. Because the events “choosing a rock CD” and “not choosing a rock CD” have the same number of favorable outcomes, half of the CDs must be rock CDs. So, there are 30 rock CDs. c. yes; Each section measures 60°. When each section is the same size, it is equally likely to spin a given number. When you increase or decrease the angle of a section, you increase or decrease the likelihood of landing on that section because its area is changing. 26. There are 5 cards, so there are 5 possible outcomes. After choosing a card, there are 4 cards left. So, the number of possible outcomes changes to 4. d. Sample answer: Each section of the spinner is the same size. So, your friend has an equal chance of landing on any of the numbers. Fair Game Review 27. 28. 29. 30. x 1 = 10 5 x 1 • 10 = • 10 10 5 x = 2 2. a. Angle 1 2 3 4 5 6 Measure 60° 60° 90° 45° 45° 60° Section 3 measures 90° and makes up one-quarter of the spinner. Your chance of landing on 3 is greater than the other numbered sections. 60 20 = n 7 60 • 7 = 20 • n 420 = 20n b. 21 = n Angle 1 2 3 4 5 6 Measure 60° 120° 90° 45° 30° 15° 1 w = 3 36 1 w • 36 = • 36 3 36 12 = w 25 100 = b 17 25 • b = 100 • 17 25b = 1700 b = 68 31. C; S = 2lw + 2lh + 2 wh = 2(12)(6) + 2(12)(5) + 2(6)(5) = 144 + 120 + 60 = 324 The surface area of the rectangular prism is 324 in.2 Section 2 measures 120° and makes up one-third of the spinner. Your chance of landing on 2 is greater than the other numbered sections. Answer should include, but is not limited to: Students should explain that the rules still make sense, but the game is not fair because of the unequal sections. 3. The rules of the game are fair for Activities 1 and 2b. The sum of the angle measures for the odd numbered pie pieces is equal to the sum of the angle measures for the even numbered pie pieces, so there is an equal likelihood of the events happening. The rules of the game are not fair for Activity 2a. The sum of the angle measures for the odd numbered pie pieces is 195°, and the sum of the angle measures for the even numbered pie pieces is 165°. So, Player 1 has a better chance of winning. 4. Sample answer: You can describe an event as impossible, unlikely to occur, likely to occur, certain, or equally likely to happen or not happen. 5. It is impossible to spin an 8 in Activity 1 because the numbers on the spinner are only 1 through 6. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 287 Chapter 10 6. Sample answers: medical fields, weather forecasters, insurance policy writers, various sports managers. 10.2 On Your Own (pp. 408 –409) 1. Because the probability of landing a jump on a snowboard is 1 , it is equally likely to happen or not 2 happen. 2. Because the probability is 100%, it is certain that the temperature will be less than 120°F tomorrow. 4 6 2 = 3 3. P(greater than 2) = The probability of rolling a number greater than 2 is 2 or 66.7%. 3 7. The probability that you will grow 12 more feet is 0, so growing 12 more feet is impossible. 8. The probability of the sun rising tomorrow is 1, so it is certain that the sun will rise tomorrow. 1 of the days in July, the probability 5 1 1 of it raining on a day in July is . Because is close to 5 5 1 , it is unlikely that it will rain on a day in July. 4 9. Because it rains on 10. Your probability of playing the correct note on a violin is 50%, so it is equally likely to play the correct note or not to play the correct note. number of red shirts total number of shirts 1 = 10 11. P( red ) = 4. The number cube has only the numbers 1 through 6. So, rolling a number 7 is impossible, and its probability is 0 or 0%. number of short straws total number of straws 1 n = 15 75 75 = 15n 5. P(short ) = The probability of choosing a red shirt is number of green shirts total number of shirts 2 = 10 1 = 5 12. P(green ) = 5 = n There are 5 short straws. The probability of choosing a green shirt is 10.2 Exercises (pp. 410 –411) Vocabulary and Concept Check number of shirts that are not white total number of shirts 9 = 10 of the number of favorable outcomes to the number of possible outcomes. than 1, because there can never be more favorable outcomes than total possible outcomes. 3. Sample answer: An impossible event is a lake in Florida freezing during the summer. A certain event is the sun setting tonight. The probability of not choosing a white shirt is number of shirts that are not black total number of shirts 8 = 10 4 = 5 14. P( not black ) = 4. You should spin Spinner B when you want to move 5. either; Both spinners have the same number of sections 9 , 10 or 90%. Practice and Problem Solving down, because Spinner B has more sections labeled “Down.” 1 , or 20%. 5 13. P( not white) = 1. To find the probability of an event, you find the ratio 2. no; The probability of an event can never be greater 1 , or 10%. 10 The probability of not choosing a black shirt is 4 , 5 or 80%. labeled “Forward.” 3 of the time, so it is likely that 4 your soccer team will win. 6. Your soccer team wins 288 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 c. There are six numbers greater than 6 (7, 8, 9, 10, 11, number of orange shirts total number of shirts 0 = 10 = 0 15. P(orange) = and 12). P(greater than 6) = The probability of rolling a number greater than 6 1 is . So, it is equally likely that you will roll a 2 number greater than 6 or not greater than 6. The probability of choosing an orange shirt is 0 or 0%. 16. The numerator should be the number of shirts that are not blue, instead of the number of shirts that are blue. 20. 6 3 = 10 5 Father’s Genes P( not blue) = number of prize winners 17. P( winning a prize) = total number of people n 0.05 = 400 20 = n Mother’s Genes X X X XX XX Y XY XY 21. The probability of two parents having a boy or having a There will be 20 people who win a prize in the contest. number of winning ducks total number of ducks n 0.24 = 25 6 = n 18. a. P( winning ) = girl is equally likely because there are two ways the genes can combine to create a girl and two ways the genes can combine to create a boy. 22. a. Parent 1 C s Parent 2 The number of winning ducks is 6, so there are 25 − 6 = 19 not winning ducks. C CC Cs s Cs ss P(CC ) = number of not winning ducks b. P( not winning) = total number of ducks 19 = 25 = 0.76 outcome of CC 1 = total number of outcomes 4 The probability of a child having the gene 1 combination is , or 25%. 4 Because 0.76 is close to 0.75, it is likely that you will not choose a winning duck. 19. a. There are eight numbers less than 9 (1, 2, 3, 4, 5, 6, 7, and 8). P(less than 9) = 6 1 = 12 2 b. P(curly) = number of outcomes with a C 3 = total numbers of outcomes 4 The probability of a child having curly hair is 3 , or 4 75%. 8 2 = 12 3 The probability of rolling a number less than 9 is Fair Game Review 2 . 3 2 3 is close to , it is likely that you will roll 3 4 a number less than 9. Because 23. x + 5 < 9 x < 4 1 3 4 5 6 7 −5 −4 −3 −2 24. b − 2 ≥ −7 b. There are four multiples of 3 (3, 6, 9, and 12). 4 1 P( multiple of 3) = = 12 3 2 b ≥ −5 −8 −7 −6 1 The probability of rolling a multiple of 3 is . 3 1 1 Because is close to , it is unlikely that you will 3 4 roll a multiple of 3. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 289 Chapter 10 25. 6. Sample answer: Most likely this is true because there are w 3 − 3 < w, or 1 > − only 20 chips in the bag and you did not select an orange chip in 50 tries. However, you cannot say this for certain because there may be 1 orange chip in the bag and you never selected it. w > −3 −6 26. −5 −4 −3 −2 −1 7. Sample answer: 0 6 ≤ −2 g −3 ≥ g , or Green Orange g ≤ −3 Yellow Red Blue −6 −5 −4 −3 −2 −1 0 8. a. yes; Because the sizes of the sections are equal, each 27. C; 46 + 135 + 86 + x = 360 outcome is equally likely to occur. 267 + x = 360 b. no; Because the sizes of the sections are not equal, x = 93 each outcome is not equally likely to occur. c. no; Because the sizes of the sections are not equal, Section 10.3 each outcome is not equally likely to occur. 10.3 Activity (pp. 412–413) 10.3 On Your Own (pp. 415 –416) 1. a. Check students’ work. 1. The bar graphs shows 4 twos, 11 fours, and 6 sixes. So, b. Check students’ work. an even number was rolled 4 + 11 + 6 = 21 times in a total of 50 rolls. c. Check students’ work. Relative frequencies should get closer to the probabilities of 1 . 2 number of times the event occurs total number of trials 21 P(even ) = 50 P(event ) = d. Check students’ work. Relative frequencies should get closer to the probabilities of 1 . 2 The experimental probability is 2. a. no; The relative frequencies can help you estimate the number of each type of chip in the bag, but you cannot be sure of the exact numbers. b. Sample answer: 100 times; The greater the number of times you perform the experiment, the more accurate your approximations will be. 3. a. no; Just because there are two outcomes does not mean that each outcome is equally likely. b. no; Each outcome is not equally likely. Check students’ work. 4. Sample answer: You can find the probability of an event occurring based on a relative frequency. You randomly draw a marble from a bag and replace it. You do this 50 times. You draw a red marble 25 times. So, the 1 probability of drawing a red marble is , or 50%. 2 1 , or 50%. 2 The relative frequency of rolling an odd number should 1 be close to . So, your friend should roll an odd number 2 about 250 times. 5. The probability of rolling an odd number is 2. 21 , 0.42, or 42%. 50 number of times the event occurs total number of trials 5 P(defective jeans) = 200 P(event ) = To make a prediction, multiply the probability of defective jeans by the number of jeans shipped. 5 • 5000 = 125. 200 So, you can expect that there will be 125 defective pairs of jeans when 5000 are shipped. 3. P( X) = number of Xs 1 = total number of letters 7 The probability of choosing an X is 1 , or about 14.3%. 7 number of odd sections total number of sections n 0.6 = 10 0.6(10) = n 4. P(odd ) = 6 = n There are 6 sections that have odd numbers. 290 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 5. 7. An even number was spun 6 + 11 + 7 = 24 times. 1 • 540 = 90 6 You would expect 90 bobbleheads to be won. relative frequency = 24 50 12 = 25 6. The bar graphs shows 53 twos, 50 threes, 52 fours, 49 = fives, and 48 sixes. So, a number greater than 1 was rolled 53 + 50 + 52 + 49 + 48 = 252 times in a total of 300 rolls. number of times the event occurs total number of trials 252 P(greater than 1) = 300 21 = 25 P(event ) = The experimental probability is 21 , or 84%. 25 Because there are 5 possible outcomes for numbers greater than 1 on a number cube (2, 3, 4, 5, and 6), the theoretical probability of rolling a number greater than 1 5 1 is = 83 %, which is close to the experimental 6 3 probability. 10.3 Exercises (pp. 417–419) an experiment and find the ratio of the number of times the event occurs to the total number of trials in the experiment. 2. yes; You could flip tails 7 out of 10 times, but with more trials the probability of flipping tails should get closer to 0.5. 3. An event that has a theoretical probability of 0.5 means there is a 50% chance you will get a favorable outcome. 4. Sample answer: The theoretical probability of spinning red on a spinner with four equal sections colored red, 1 blue, green, and yellow is . 4 5. Because the pollster surveys only a subset of the population, experimental probability should be used. The pollster cannot find theoretical probability without surveying every person who will participate in the election. Practice and Problem Solving 6. The total number of times the spinner was spun is 8 + 6 + 9 + 11 + 9 + 7 = 50. number of times 6 spun 7 = total number of spins 50 Copyright © Big Ideas Learning, LLC All rights reserved. 8. A number less than 3 was spun 8 + 6 = 14 times. P(less than 3) = number of times less than 3 spun total number of spins 14 50 7 = 25 = The experimental probability of spinning a number less 7 than 3 is , or 28%. 25 spun is 6 + 9 + 11 + 9 + 7 = 42. 1. To find the experimental probability of an event, perform The relative frequency of spinning a 6 is The relative frequency of spinning an even number is 12 , or 48%. 25 9. The total number of times a number that is not 1 was Vocabulary and Concept Check relative frequency = number of times an even number spun total number of spins P ( not 1) = number of times not 1 spun 42 21 = = total number of spins 50 25 The experimental probability of not spinning a 1 is 21 , 25 or 84%. 10. A 1 or a 3 was spun 8 + 9 = 17 times. P (1 or 3) = number of times a 1 or a 3 spun 17 = total number of spins 50 The experimental probability of spinning a 1 or a 3 is 17 , or 34%. 50 11. P (7 ) = number of times 7 spun 0 = = 0 total number of spins 50 The experimental probability of spinning a 7 is 0, or 0%. 12. P(at least 1 cracked egg ) number of cartons with at least 1 cracked egg total number of cartons checked 3 = 20 = The experimental probability that a carton of eggs has at 3 least one cracked egg is , or 15%. 20 7 , or 14%. 50 Big Ideas Math Red Accelerated Worked-Out Solutions 291 Chapter 10 13. P( vowels) = number of vowels chosen 3 = total number of letters chosen 7 3 • 105 = 45 7 1 • 20 = 5 4 You can expect 5 cards to have flowers on them. number of strikes total number of chips 3 9 = 10 n 3 • n = 9 • 10 3n = 90 There are 30 chips in the bag. 1 1 , or about 33 %. 3 3 number of sections with 1 1 = total number of sections 6 The probability of spinning a 1 is 22. P(strike) = n = 30 number of red sections 2 1 = = total number of sections 6 3 The probability of spinning red is 25 , or 26 about 96.2%. number of cards chosen with flowers 1 14. P(flowers) = = total number of cards chosen 4 16. P(1) = number of letters not Z 25 = total number of letters 26 The probability of choosing any letter except Z is You can expect 45 tiles to be vowels. 15. P( red ) = 21. P(letter except Z) = 23. P( pop song ) = pop songs played total songs played n 80 0.45(80) = n 0.45 = 2 1 , or 16 %. 6 3 36 = n There are 36 pop songs on your MP3 player. 17. P(odd ) = number of odd sections 3 1 = = total number of section 6 2 The probability of spinning an odd number is 1 , or 50%. 2 18. P( multiple of 2) number of sections with a multiple of 2 total number of sections 3 = 6 1 = 2 = 1 The probability of spinning a multiple of 2 is , or 50%. 2 number of sections less than 7 total number of sections 6 = 6 =1 19. P(less than 7) = The probability of spinning a number less than 7 is 1, or 100%. 20. P(9) = number of females total number in class 16 = 16 + 20 16 = 36 4 = 9 24. a. P(female) = The probability of randomly choosing a female is 4 , 9 or about 44.4%. number of females total number in class 4 f = 9 45 4 • 45 = 9 • f b. P(female) = 180 = 9 f 20 = f Number of males = 45 − 20 = 25 So, 25 − 20 = 5 males joined the class. number of sections with 9 0 = = 0 total number of sections 6 The probability of spinning a 9 is 0, or 0%. 292 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 25. P ( 4) = number of “4” spins 37 = total number of spins 200 29. a. P(TT) = The experimental probability of spinning a 4 is 37 , 200 or 18.5%. P( 4) = number of “4” sections 1 = total number of sections 5 The theoretical probability of spinning a 4 is 1 , or 20%. 5 number of “3” spins 39 = total number of spins 200 39 , 200 number of “3” sections 1 = total number of sections 5 number of TT’s 22 11 = = number of trials 100 50 The experimental probability of flipping two tails is 11 , or 22%. 50 expected number of TT’s total number of trials n 11 = 50 600 n 11 • 600 = • 600 50 600 132 = n P(TT ) = 1 , or 20%. 5 The experimental probability is very close to the theoretical probability. 27. P(greater than 4) = 50 = n b. P(TT) = or 19.5%. The theoretical probability of spinning a 3 is expected number of TT’s total number of trials 1 n = 12 600 600 = 12n You can expect to flip two tails 50 times in 600 trials. The experimental probability of spinning a 3 is P(3) = The experimental probability of flipping two tails is 1 1 , or 8 %. 12 3 P(TT) = The experimental probability is close to the theoretical probability. 26. P (3) = number of TT’s 1 = number of trials 12 number of spins greater than 4 total number of spins 40 200 1 = 5 = You can expect to flip two tails 132 times in 600 trials. c. Sample answer: A larger number of trials should result in a more accurate probability, which gives a more accurate prediction. The experimental probability of spinning a number 1 greater than 4 is , or 20%. 5 number of sections greater than 4 total number of sections 1 = 5 P(greater than 4) = The theoretical probability of spinning a number greater 1 than 4 is , or 20%. 5 The experimental and theoretical probabilities are equal. 28. theoretical; Spinning the spinner 10,000 times is very time consuming if using experimental probability. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 293 Chapter 10 30. P( 2) = number of times sum of 2 rolled 2 1 = = total number of rolls 60 30 31. P ( 2) = P(3) = number of times sum of 3 rolled 4 1 = = total number of rolls 60 15 P (3) = number of favorable outcomes 2 1 = = number of possible outcomes 36 18 P( 4) = number of times sum of 4 rolled 5 1 = = total number of rolls 60 12 P ( 4) = number of favorable outcomes 3 1 = = number of possible outcomes 36 12 P(5) = number of times sum of 5 rolled 6 1 = = total number of rolls 60 10 P (5) = number of favorable outcomes 4 1 = = number of possible outcomes 36 9 P(6) = number of times sum of 6 rolled 13 = total number of rolls 60 P ( 6) = number of favorable outcomes 5 = number of possible outcomes 36 P(7) = number of times sum of 7 rolled 10 1 = = total number of rolls 60 6 P (7 ) = number of favorable outcomes 6 1 = = number of possible outcomes 36 6 P(8) = number of times sum of 8 rolled 6 1 = = total number of rolls 60 10 P (8) = number of favorable outcomes 5 = number of possible outcomes 36 P(9) = number of times sum of 9 rolled 8 2 = = total number of rolls 60 15 P (9 ) = number of favorable outcomes 4 1 = = number of possible outcomes 36 9 number of favorable outcomes 1 = number of possible outcomes 36 P(10) = number of times sum of 10 rolled 2 1 = = total number of rolls 60 30 P (10) = number of favorable outcomes 3 1 = = number of possible outcomes 36 12 P(11) = number of times sum of 11 rolled 3 1 = = total number of rolls 60 20 P (11) = number of favorable outcomes 2 1 = = number of possible outcomes 36 18 P(12) = number of times sum of 12 rolled 1 = total number of rolls 60 P (12) = number of favorable outcomes 1 = number of possible outcomes 36 Each sum is not equally likely because they do not have the same outcomes. The event with the greatest experimental probability is rolling a sum of 6. So, a sum of 6 is most likely. Each sum is not equally likely because they do not have the same outcomes. The event with the greatest probability is rolling a sum of 7. So, a sum of 7 is most likely. 32. The experimental and theoretical probabilities from Exercises 30 and 31 are similar. 33. a. Sample answer: After 500 trials, you would expect a sum of 6, 7, or 8 to be most likely. After 1000 or 10,000 trials, a sum of 7 would probably be most likely. b. As the number of trials increases, the experimental probability approaches the theoretical probability. 34. a. Check students’ work. The cup should land on its side most of the time. b. Check students’ work. c. Check students’ work. d. more likely; Due to the added weight, the cup will be more likely to hit open-end up and thus more likely to land open-end up. Some students may justify by performing multiple trials with a quarter taped to the bottom of the cup. 294 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 Fair Game Review 35. 4. a. 10,000 passswords × I = Prt 16 = 200( r )( 2) 16 = 400r 0.04 = r The annual interest rate is 0.04, or 4%. 36. ≈ 16.7 minutes It could take up to 16.7 minutes, or 16 minutes 40 seconds to guess the password. b. 100,000 passswords × I = Prt 18 26.25 = 500( r ) 12 26.25 = 750r It could take up to 2.8 hours to guess the password. c. 308,915,776 passswords × 1 h 1 day × 60 min 24 h ≈ 357.5 days 3 Section 10.4 1 min 600 passwords × The annual interest rate is 0.035, or 3.5%. 3 ft 27 ft 3 3 = 243 ft 3 = 9 yd × 1 yd3 1 yd 1 min 1h × 60 min 600 passwords ≈ 2.8 hours 0.035 = r 37. D; 9 yd3 × 1 min 600 passwords It could take up to 357.5 days to guess the password. d. 2,821,109,907,456 passswords × 10.4 Activity (pp. 420 –421) 1 day 1 h × 60 min 24 h 1 yr × 365 days 1. a. 000; 999; 1000 × b. 10; 10; 10; Sample answer: Multiply to find the total number of possible combinations: 10 • 10 • 10 = 1000 combinations. ≈ 8945.7 years c. 40 • 40 • 40 = 64,000 combinations d. 10 • 10 • 10 • 10 = 10,000 combinations e. The lock in part (c) is most difficult to guess because it has the greatest number of possible combinations compared to the other two locks. 2. a. There are 10 choices for each digit. 10 • 10 • 10 • 10 = 10,000 It could take up to 8945.7 years to guess the password. 10.4 On Your Own (pp. 422–424) 1. Crust Style Outcome Thin Hawaiian Mexican Pepperoni Veggie Thin Crust Hawaiian Thin Crust Mexican Thin Crust Pepperoni Thin Crust Veggie Stuffed Hawaiian Mexican Pepperoni Veggie Stuffed Crust Hawaiian Stuffed Crust Mexican Stuffed Crust Pepperoni Stuffed Crust Veggie Deep Dish Hawaiian Mexican Pepperoni Veggie Deep Dish Crust Hawaiian Deep Dish Crust Mexican Deep Dish Crust Pepperoni Deep Dish Crust Veggie There are 10,000 possible passwords. b. There are 10 choices for each digit. 10 • 10 • 10 • 10 • 10 = 100,000 There are 100,000 possible passwords. c. There are 26 choices for each letter. 26 • 26 • 26 • 26 • 26 • 26 = 308,915,776 There are 308,915,776 possible passwords. d. There are 26 + 10 = 36 choices for each character. 36 • 36 • 36 • 36 • 36 • 36 • 36 • 36 = 2,821,109,907,456 There are 2,821,109,907,456 possible passwords. The password requirement in part (d) in most secure because it has the greatest number of possible passwords. 3. Sample answer: You can use an organized list, a table, a tree diagram, or multiplication. 1 min 600 passwords There are 12 different outcomes. So, there are 12 different pizzas possible. 2. Event 1: Spinning the spinner (4 outcomes) Event 2: Choosing a number from 1 to 5 (5 outcomes) 4 × 5 = 20 There are 20 possible outcomes. 3. Event 1: Choosing a T-shirt (4 outcomes) Event 2: Choosing a pair of jeans (5 outcomes) Event 3: Choosing a pair of shoes (5 outcomes) 4 × 5 × 5 = 100 You can make 100 different outfits. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 295 Chapter 10 4. There are four favorable outcomes in the sample space for rolling at most 4 and flipping heads: 1H, 2H, 3H and 4H. P(event ) = number of favorable outcomes number of possible outcomes 4 12 1 = 3 P(at most 4 and heads) = The probability is 1 1 , or 33 %. 3 3 5. There are four favorable outcomes in the sample space for flipping at least two tails: HTT, THT, TTH, and TTT. P(event ) = number of favorable outcomes number of possible outcomes 4 8 1 = 2 P(at least 2 tails) = 1 The probability is , or 50%. 2 6. Using the table from Exercise #31 of Section 10.3, there is one favorable outcome in the sample space for rolling double threes. P(event ) = P(double threes) = The probability is number of favorable outcomes number of possible outcomes 1 36 1 7 , or 2 %. 36 9 7. There is one favorable outcome in the sample space for choosing a stuffed crust Hawaiian pizza. P(event ) = number of favorable outcomes number of possible outcomes 1 P(double threes) = 8 1 1 The probability is , or 12 %. 8 2 10.4 Exercises (pp. 425 –427) Vocabulary and Concept Check 1. A sample space is the set of all possible outcomes of an event. Use a table or tree diagram to list all the possible outcomes. 2. To use the Fundamental Counting Principle, first identify the number of possible outcomes for each event. Then the total number of possible outcomes is the product of these numbers. 296 Big Ideas Math Red Accelerated Worked-Out Solutions 3. One way is to use a tree diagram to find the total number of possible outcomes. Another way is to use the Fundamental Counting Principle by finding the number of possible outcomes of spinning the spinner and multiplying it by the number of possible outcomes of rolling the number cube. The total number of possible outcomes is 30. 4. Sample answer: An example of a compound event is drawing two names out of a hat. Practice and Problem Solving 5. Event 1: Choosing a number from 0 to 49 (50 outcomes) Event 2: Choosing a number from 0 to 49 (50 outcomes) Event 3: Choosing a number from 0 to 49 (50 outcomes) 50 × 50 × 50 = 125,000 There are 125,000 possible combinations for the lock. 6. Event Time Outcome Miniature Golf 1 P.M. – 3 P.M. Miniature Golf, 1 P.M. – 3 P.M. 6 P.M. – 8 P.M. Miniature Golf, 6 P.M. – 8 P.M. Laser Tag 1 P.M. – 3 P.M. Laser Tag, 1 P.M. – 3 P.M. 6 P.M. – 8 P.M. Laser Tag, 6 P.M. – 8 P.M. Roller Skating 1 P.M. – 3 P.M. Roller Skating, 1 P.M. – 3 P.M. 6 P.M. – 8 P.M. Roller Skating, 6 P.M. – 8 P.M. There are 6 possible outcomes for the birthday party. 7. Type Style Outcome Lion Realistic Realistic lion Cartoon Cartoon lion Bear Realistic Realistic bear Cartoon Cartoon bear Hawk Realistic Realistic hawk Cartoon Cartoon hawk Dragon Realistic Realistic dragon Cartoon Cartoon dragon There are 8 possible outcomes for the new school mascot. 8. Event 1: There are 3 possible sizes. Event 2: There are 7 possible flavors. 3 × 7 = 21 There are 21 possible beverages. 9. Event 1: There are 4 possible amounts of memory. Event 2: There are 5 possible colors. 4 × 5 = 20 There are 20 possible types of MP3 players. 10. Event 1: There are 3 possible suits. Event 2: There are 2 possible wigs. Event 3: There are 4 possible talents. 3 × 2 × 4 = 24 There are 24 possible types of clowns. Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 11. Event 1: There are 5 possible appetizers. 15–20. Spinner Event 2: There are 4 possible entrées. Coin Outcome 1 H T 1H 1T 2 H T 2H 2T 3 H T 3H 3T 4 H T 4H 4T 5 H T 5H 5T Event 3: There are 3 possible desserts. 5 × 4 × 3 = 60 There are 60 possible different meals. 12. Method 1: Type Type 1 Type 2 Type 3 Size Outcome Size 1 Type 1, Size 1 Size 2 Type 1, Size 2 Size 3 Type 1, Size 3 Size 1 Type 2, Size 1 Size 2 Type 2, Size 2 Size 3 Type 2, Size 3 Size 1 Type 3, Size 1 Size 2 Type 3, Size 2 Size 3 Type 3, Size 3 15. There is one favorable outcome in the sample space for spinning a 1 and flipping heads. number of favorable outcomes number of possible outcomes 1 P(1 and H) = 10 P(event ) = The store sells a total of 9 different note cards. The probability is Method 2: Event 1: There are 3 possible types. 1 , or 10%. 10 16. There are two favorable outcomes in the sample space for Event 2: There are 3 possible sizes. spinning an even number and flipping heads: 2H and 4H. 3×3 = 9 number of favorable outcomes number of possible outcomes 2 P(even and H) = 10 1 = 5 P(event ) = The store sells a total of 9 different note cards. 13. The total number of outcomes is the product of the possible outcomes of each event, not the sum. Event 1: Question 1 (2 possible answers) Event 2: Question 2 (2 possible answers) The probability is Event 3: Question 3 (2 possible answers) Event 4: Question 4 (2 possible answers) 17. There are two favorable outcomes in the sample space for Event 5: Question 5 (2 possible answers) spinning a number less than 3 and flipping tails: 1T and 2T. 2 × 2 × 2 × 2 × 2 = 32 The quiz can be answered 32 different ways. Principle. b. Let G = green, B = blue, R = red, and Y = yellow. Marble 2 Outcome G B R R B Y G R Y G B Y Y number of favorable outcomes number of possible outcomes 2 P(less than 3 and T) = 10 1 = 5 P(event ) = 14. a. Use a tree diagram or the Fundamental Counting Marble 1 1 , or 20%. 5 G B R GB GR GY BG BR BY RG RB RY YG YB YR There are 12 possible outcomes. Using the Fundamental Counting Principle, there are 4 possible outcomes for choosing the first marble, and 3 possible outcomes for choosing the second marble. So, there are 4 × 3 = 12 possible outcomes. The probability is 1 , or 20%. 5 18. There are no favorable outcomes in the sample space for spinning a 6 and flipping tails. number of favorable outcomes number of possible outcomes 0 P(6 and T) = 10 = 0 P(event ) = The probability is 0, or 0%. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 297 Chapter 10 19. There are four favorable outcomes in the sample space for not spinning a 5 and flipping heads: 1H, 2H, 3H, and 4H. P(event ) = 4 10 2 = 5 for spinning a prime number and not flipping heads: 2T, 3T, and 5T. The probability is Coin H 1 (red) T H 2 (blue) T H 3 (yellow) T spinning an even number, flipping tails, then spinning an odd number: 2T1 and 2T3. P(event ) = number of favorable outcomes number of possible outcomes 2 18 1 = 9 1 1 The probability is , or 11 %. 9 9 3 10 P(odd then H then yellow ) = 3 , or 30%. 10 Spinner Outcome 1 (red) 1 (red), H, 1 (red) 2 (blue) 1 (red), H, 2 (blue) 3 (yellow) 1 (red), H, 3 (yellow) 1 (red) 1 (red), T, 1 (red) 2 (blue) 1 (red), T, 2 (blue) 3 (yellow) 1 (red), T, 3 (yellow) 1 (red) 2 (blue), H, 1 (red) 2 (blue) 2 (blue), H, 2 (blue) 3 (yellow) 2 (blue), H, 3 (yellow) 1 (red) 2 (blue), T, 1 (red) 2 (blue) 2 (blue), T, 2 (blue) 3 (yellow) 2 (blue), T, 3 (yellow) 25. a. Event 1: There are 3 possible choices. 1 (red) 3 (yellow), H, 1 (red) Event 2: There are 3 possible choices. 2 (blue) 3 (yellow), H, 2 (blue) 3 (yellow) 3 (yellow), H, 3 (yellow) 1 (red) 3 (yellow), T, 1 (red) 2 (blue) 3 (yellow), T, 2 (blue) 3 (yellow) 3 (yellow), T, 3 (yellow) 21. There is one favorable outcome in the sample space for spinning blue, flipping heads, then spinning a 1. P(event ) = P( blue then H then 1) = The probability is 23. There are two favorable outcomes in the sample space for number of favorable outcomes number of possible outcomes 21–24. Spinner number of favorable outcomes number of possible outcomes 2 18 1 = 9 1 1 The probability is , or 11 %. 9 9 20. There are three favorable outcomes in the sample space P( prime and not H ) = P(event ) = P(odd then H then yellow ) = 2 , or 40%. 5 P(event ) = spinning an odd number, flipping heads, then spinning yellow: 1H-yellow, and 3H-yellow. number of favorable outcomes number of possible outcomes P( not spinning 5 and H) = The probability is 22. There are two favorable outcomes in the sample space for number of favorable outcomes number of possible outcomes 1 18 24. There are four favorable outcomes in the sample space for not spinning red, flipping tails, then not spinning an even number: blue-T1, blue-T3, yellow-T1, and yellowT3. P(event ) = number of favorable outcomes number of possible outcomes 4 18 2 = 9 2 2 The probability is , or 22 %. 9 9 P( not red then T then not even ) = 3×3 = 9 There are 9 possible outcomes, but only one way to guess both answers correctly. P(event ) = P( both correct ) = number of favorable outcomes number of possible outcomes 1 9 The probability that you guess the correct answers to 1 both questions is , or about 11.1%. 9 1 5 , or 5 %. 18 9 298 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 b. If you can eliminate one of the choices for each question, then you have two choices left to choose from for each question. Event 1: There are 2 possible choices. 2×2 = 4 There are 4 possible outcomes, but only one way to guess both answers correctly. P( both correct ) = P(event ) = number of favorable outcomes number of possible outcomes 1 4 The probability that your choice is correct is 1 , or 25%. 4 1 1000 1 , 1000 or 0.1%. b. There are 1000 possible combinations. With 5 tries, you would guess 5 out of the 1000 possibilities. So, the probability of getting the correct combination is 5/1000, or 0.5%. Event 2: There are 10 possible choices. 10 × 10 = 100 There are 100 possible outcomes, but only one way to guess both digits correctly. 28. Event 1: 1 possible engine in the first position Event 2: 8 possible train cars in the second position number of favorable outcomes number of possible outcomes Event 3: 7 possible train cars in the third position 1 100 Event 5: 5 possible train cars in the fifth position Event 4: 6 possible train cars in the fourth position Event 6: 4 possible train cars in the sixth position The probability that your choice is correct is 1 , 100 or 1%. Event 7: 3 possible train cars in the seventh position Event 8: 2 possible train cars in the eighth position Event 9: 1 possible train car in the ninth position b. Because you know the digits are even, you have 5 choices for each digit. Event 1: There are 5 possible choices. Event 2: There are 5 possible choices. 5 × 5 = 25 There are 25 possible outcomes, but only one way to guess both digits correctly. P(event ) = There are 1000 possible outcomes, but only one way to guess all three digits correctly. P(correctly guessed) = 26. a. Event 1: There are 10 possible choices. P( both correct ) = Event 3: There are 10 possible choices. number of favorable outcomes number of possible outcomes The probability increases to P(event ) = Event 2: There are 10 possible choices. 10 × 10 × 10 = 1000 Event 2: There are 2 possible choices. P(event ) = 27. a. Event 1: There are 10 possible choices. number of favorable outcomes number of possible outcomes 1 P( both digits) = 25 The probability increases to 1 , or 4%. 25 1 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 40,320 The train can be arranged 40,320 ways. 29. a. There are 9 events, and each event has 10 possible outcomes, so a tree diagram would be too large. b. 10 × 10 × 10 × 10 × 10 × 10 × 10 × 10 × 10 = 1,000,000,000 There are 1 billion identification numbers possible. c. Answer should include, but is not limited to: Students will explain that certain number combinations are not valid for Social Security numbers. For example, the first three digits cannot be a number in the 800’s or 900’s. Also, the first three digits cannot all be zeros, the fourth and fifth digits cannot both be zeros, and the sixth through the ninth digits cannot all be zeros. 30. 10; Let the 5 candidates be represented by A, B, C, D, and E. Then, a committee of 3 people could be one of the 10 following ways: ABC, ABD, ABE, ACD, ACE, ADE, BCD, BCE, BDE, and CDE. Order does not matter. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 299 Chapter 10 b. yes; The probability of getting a green marble on the Fair Game Review second draw depends on the color of the first marble because if a green marble is drawn first, then there is a 50% chance of drawing a green marble on the second draw. If a purple marble is drawn first, then there is a 100% chance of drawing a green marble on the second draw. 31. Sample answers: adjacent: ∠XWY and ∠ZWY , ∠XWY and ∠XWV vertical: ∠VWX and ∠YWZ , ∠YWX and ∠VWZ 32. Sample answers: adjacent: ∠LJM and ∠LJK , ∠LJM and ∠NJM vertical: ∠KJL and ∠PJN , ∠PJQ and ∠MJL 3. a. Answer should include, but is not limited to: Students will perform an experiment by drawing a marble from a bag, putting it back, and drawing a second marble. The experiment should be performed 36 times. Students will record their results in a table and then draw a bar graph representing the results. Bar graphs should be neatly drawn and clearly labeled. 1 cm 1 cm 33. B; 1 cm : 1 m = = 1 : 100 = 1m 100 cm Section 10.5 10.5 Activity (pp. 428 –429) b. Answer should include, but is not limited to: Students will perform a second experiment by drawing 2 marbles from a bag 36 times. Students will record their results in a table and then draw a bar graph representing the results. Bar graphs should be neatly drawn and clearly labeled. 1. a. First draw: Second draw: GG GG GP GG GG GP PG PG PP will use the results of the experiments in parts (a) and (b) to determine the experimental probability of drawing two green marbles. number of favorable outcomes P(green, green ) = number of possible outcomes = c. Answer should include, but is not limited to: Students d. The second experiment represents dependent events 4 9 The probability that both marbles are green is 4 . 9 b. no; The probability of getting a green marble on the second draw does not depend on the color of the first marble because the probability of getting a green marble is the same for both draws. 2. a. because the probability of the second marble being green or purple depends on the color of the first marble. The first experiment represents independent events because the color of the second marble does not depend on the color of the first marble. 4. Two events are dependent if the occurrence of one event does affect the likelihood that the other event will occur. Two events are independent if the occurrence of one event does not affect the likelihood that the other event will occur. Sample answer: An example of dependent events is drawing two names out of a basket without replacing the first name. An example of independent events is flipping a coin twice. First draw: Second draw: GG GP GG GP PG PG number of favorable outcomes P(green, green ) = number of possible outcomes 2 6 1 = 3 This event is not more likely than the event in 1 Activity 1 because the probability of is not 3 4 greater than the probability of . 9 300 Big Ideas Math Red Accelerated Worked-Out Solutions outcome of spinning a spinner. So, the events are independent. 6. The outcome of selecting the first group leader does = The probability that both marbles are green is 5. The outcome of rolling a number cube does not affect the 1 . 3 affect the outcome of selecting the second group leader because there are fewer students to choose from when picking the second group leader. So, the events are dependent. 7. The outcome of spinning red on one spinner does not affect the outcome of spinning green on the other spinner. So, the events are independent. Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 2 2 ; ; Find the product of the 3 3 2 2 4 probabilities, which is • = . 3 3 9 8. For Activity 1: So, the probability of drawing two green marbles in 4 Activity 1 is . 9 2 1 For Activity 2: ; ; Sample answer: Find the product 3 2 2 1 2 1 of the probabilities, which is • = = . 3 2 6 3 So, the probability of drawing two green marbles 1 in Activity 2 is . 3 10.5 On Your Own (pp. 430 –432) 2 1. P( multiple of 2) = 5 1 P( heads) = 2 P( A and B) = P( A) • P( B) P(multiple of 2 and heads) = P(multiple of 2) • P(heads) 2 1 = • 5 2 1 = 5 The probability of spinning a multiple of 2 and flipping 1 heads is , or 20%. 5 2. There are 88 other audience members who are not you, your relatives, or your friends. Choosing an audience member changes the number of audience members left. So, the events are dependent. 88 22 = 100 25 87 29 P(second other audience member ) = = 99 33 P(first other audience member ) = P( A and B ) = P( A) • P( B after A) P( 2 other audience members) = P(1st other ) • P( 2nd other after 1st ) 22 29 • 25 33 58 = 75 = 3. P( #1 correct and #2 correct and #3 correct ) = P( #1 correct ) • P( #2 correct ) • P( #3 correct ) 1 1 1 • • 4 4 4 1 = 64 = The probability of answering all three questions correctly 1 , or about 1.56%. This is greater than the probability is 64 in Example 3. So, the probability of answering all three questions correctly increases when one choice is eliminated. 10.5 Exercises (pp. 433 –435) 1. All four questions have first events that are the same, because “choosing a 1” is the same as “choosing a green chip” and “choosing a number less than 2.” However, the second event of question #1 does not match the others. Of the chips remaining, the even numbers are also the chips that are not red, and these chips are blue and yellow, not just blue. P(1 and blue) = P(1) • P( blue after 1) 1 2 • 6 5 1 = 15 = P(1 and even ) = P(1) • P(even after 1) 1 3 • 6 5 1 = 10 = 2. When events A and B are independent, the probability of both events is the probability of event A times the probability of event B. When events A and B are dependent, the probability of both events is the probability of event A times the probability of event B after event A occurs. Practice and Problem Solving 3. The outcome of the first roll does not affect the outcome of the second roll. So, the events are independent. 4. After you draw your lane number, there is one less lane number available for your friend. So, the events are dependent. The probability that you, your relatives, and your friends are not chosen to be either of the first two contestants 58 , or about 77.3%. is 75 Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 301 Chapter 10 5. P( A and B) = P( A) • P( B ) P(3 and heads) = P(3) • P( heads) 1 1 • 4 2 1 = 8 = 9. P(first is 5) = P( A and B) = P( A) • P( B after A) P(5 and 6) = P(5) • P(6 after 5) 2 1 • 4 2 1 = 4 The probability of choosing a 5 and then a 6 is 1 , or 42 about 2.4%. = 10. P(first is odd ) = The probability of spinning an even number and flipping 1 tails is , or 25%. 4 P( A and B) = P( A) • P( B ) P(greater than 1 and tails) = P(greater than 1) • P( tails) 3 1 • 4 2 3 = 8 = The probability of spinning a number greater than 1 and 3 flipping tails is , or 37.5%. 8 8. 1 1 • 7 6 1 = 42 = P( A and B) = P( A) • P( B ) P(even and tails) = P(even ) • P( tails) 7. 1 6 P(second is 6) = The probability of spinning a 3 and flipping heads is 1 , or 12.5%. 8 6. 1 7 P( A and B) = P( A) • P( B) P( not 2 and heads) = P( not 2) • P( heads) 3 1 • 4 2 3 = 8 = The probability of not spinning a 2 and flipping heads is 3 , or 37.5%. 8 3 7 P(second is 20) = 1 6 P( A and B) = P( A) • P( B after A) P(odd and 20) = P(odd ) • P( 20 after odd ) 3 1 • 7 6 1 = 14 = The probability of choosing an odd number and then 20 is 1 , or about 7.1%. 14 11. P(first is less than 7) = 2 7 P(second is multiple of 4) = 2 1 = 6 3 P( A and B) = P( A) • P( B after A) P(less than 7 and multiple of 4) = P(less than 7) multiple of 4 • P after less than 7 2 1 = • 7 3 2 = 21 The probability of choosing a number less than 7 and 2 then a multiple of 4 is , or about 9.5%. 21 302 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 4 7 12. P(first is even ) = P(second is even ) = 16. P(choose correct path at first fork ) = 3 1 = 6 2 P(choose correct path at second fork ) = P( both even ) = P(even ) • P(even after even ) P( both correct paths) = P(correct 1st path ) • P(correct 2nd path ) 4 1 • 7 2 2 = 7 1 1 • 2 2 1 = 4 = = The probability of choosing two even numbers is 2 , or 7 The probability that you are still on the correct path is 13. The events are dependent, not independent. 17. P(first is purple) = 1 4 3 14 P( A and B ) = P( A) • P( B after A) P( A and B) = P( A) • P( B after A) P( both purple) = P( purple) • P( purple after purple) P( red and green ) = P(red ) • P(green after red ) 4 3 • 15 14 2 = 35 = 1 1 • 4 3 1 = 12 = The probability that both balloons are purple is 14. The tree diagram shows that three marbles are available for the first draw and only two marbles are available for the second draw. So, the events are dependent. 2 , or 35 about 5.7%. 18. P( A and B and C ) = P( A) • P( B ) • P(C ) P( 4 and heads and 7) = P( 4) • P( heads) • P(7) 2 1 = 4 2 1 P(second is silver ) = 3 15. P(first is silver ) = 1 1 1 • • 9 2 9 1 = 162 = P( A and B) = P( A) • P( B after A) 1 1 1 • = 2 3 6 The probability that both are silver hoop earnings is or about 16.7%. 4 15 P(second is purple) = 1 3 P( both silver ) = P(silver ) • P(silver ) = 1 , 4 or 25%. about 28.6%. P(second is green ) = 1 2 P( A and B ) = P( A) • P( B after A) P( A and B) = P( A) • P( B after A) P(first is red) = 1 2 1 , 6 The probability is 19. 1 , or about 0.6%. 162 P( A and B and C ) = P( A) • P( B) • P(C ) P(odd and heads and 3) = P(odd ) • P( heads) • P(3) 5 1 1 • • 9 2 9 5 = 162 = The probability is Copyright © Big Ideas Learning, LLC All rights reserved. 5 , or about 3.1%. 162 Big Ideas Math Red Accelerated Worked-Out Solutions 303 Chapter 10 20. P( A and B and C ) = P( A) • P( B ) • P(C ) even and tails P = P(even ) • P( tails) • P(odd ) and odd 4 1 5 = • • 9 2 9 10 = 81 The probability is 10 , or about 12.3%. 81 P( A and B and C ) = P( A) • P( B) • P(C ) 21. P( not 5 and heads and 1) = P( not 5) • P( heads) • P(1) 8 1 1 • • 9 2 9 4 = 81 = 4 The probability is , or about 4.9%. 81 22. 24. If 20% of the shoes are black, then 80% are not black. P( A and B and C ) = P( A) • P( B) • P(C ) P( none black ) = P( not black ) • P( not black ) • P( not black ) = 0.80 • 0.80 • 0.80 = 0.512 The probability that none of the shoes are black is 0.512, or 51.2%. 25. a. no; If you and your best friend were in the same group, then the probability that you both are chosen would be 0 because only one leader is chosen from each group. Because the probability that both you and 1 your best friend are chosen is , you and your best 132 friend are not in the same group. b. P( both are chosen ) = P( you are chosen ) • P(friend is chosen ) 1 1 = • x 132 12 12 = x 132 1 = x 11 P( A and B and C ) = P( A) • P( B) • P(C ) odd and not heads not P = P(odd) • P heads • P( not 6) and not 6 5 1 8 = • • 9 2 9 20 = 81 The probability is 20 , or about 24.7%. 81 15 23. P( not chosen first ) = 16 14 15 13 P( not chosen third) = 14 12 P( not chosen fourth ) = 13 P( not chosen second) = P( not one of first four students chosen ) = P( not 1st ) • P( not 2nd ) • P(not 3rd ) • P(not 4th ) 15 14 13 12 • • • 16 15 14 13 12 = 16 3 = 4 The probability that your best friend is chosen as a 1 group leader is , or about 9.1%. 11 c. The probability that you are chosen to be a leader 1 , so there are 12 students in your group. The 12 probability that your best friend is chosen to be a leader 1 is , so there are 11 students in that group. The total 11 number of students in the class is 12 + 11 = 23. is 26. 25% = 25 1 = 100 4 Eliminate all but 2 of the choices in each question. a. P( both correct ) = P(one question correct ) • P( the other question correct ) = The probability that you are not one of the first four 3 students chosen is , or 75%. 4 1 1 1 = • 4 2 2 1 3 b. 8 % = 25 25 1 1 • = % = 3 3 100 12 Eliminate one of the choices in one of the questions and eliminate two of the choices in the other question. P( both correct ) = P(one question correct ) • P( the other question correct ) 1 1 1 = • 12 4 3 304 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 2. Sample answer: Place 7 green and 3 red marbles in a bag. Fair Game Review Let the green marbles represent a win and the red marbles represent a loss. Randomly pick one marble to simulate the first game. Replace the marble and repeat two more times. This is one trial. Run 30 trials. Check students’ work. The probability should be close to 34.3% (depending on the number of trials, because that is the theoretical probability). 27. Sample answer: 608 308 908 The triangle has no congruent sides and one right angle. So, it is a right scalene triangle. 28. Sample answer: 508 1108 208 The triangle has no congruent sides and one obtuse angle. So, it is an obtuse scalene triangle. 29. Sample answer: 508 508 808 3. 1 2 3 4 5 6 7 8 9 10 11 A 7584 3762 3024 4547 1719 7938 6951 4714 0797 3300 B 3974 3805 1554 6220 0662 9551 0578 4511 3022 5454 C 8614 2725 2708 9497 1814 8552 5560 5115 9067 5351 D 2500 7320 1126 7530 6218 4321 0740 6952 2193 6319 E 4629 6487 9395 3036 2766 8043 4479 5609 6553 0387 F Sample answer: Using the spreadsheet in Example 3 and using digits 1 – 4 as successes, the experimental 8 probability is , or 0.16, or 16%. 50 The triangle has two congruent angles, and all angles are acute. So, it is an acute isosceles triangle. 30. C; For A: 2 = 0.66... 3 0.6 = 0.60 67% = 0.67 For B: 44.5% = 0.445 4 = 0.444... 9 0.46 = 0.466... For C: 0.269 = 0.269 27% = 0.270 3 = 0.2727... 11 1 ≈ 2.1429 7 214% = 2.1400 For D: 2 2.14 = 2.1414... 10.5 Extension (p. 437) Practice 1. a. Sample answer: Roll four number cubes. Let an odd number represent a correct answer and an even number represent an incorrect answer. Run 40 trials. b. Check students’ work. The probability should be “close” to 6.25% (depending on the number of trials, because that is the theoretical probability). Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 305 Chapter 10 4. Example 1: The events are independent, and 1 P( boy) = . 2 P( three boys) = P( boy) • P( boy) • P( boy) 1 1 1 • • 2 2 2 1 = 8 = The theoretical probability of having three boys is 1 , or 12.5%. 8 Example 2: The events are independent. P( rain on Monday) = 0.6 P( rain both days) = P( rain on Monday) • P( rain on Tuesday) = (0.6)(0.2) = 0.12 The theoretical probability of it raining on both Monday and Tuesday is 0.12, or 12%. Example 3: Each year, there are two possible equal outcomes: cancellation due to weather or no cancellation. So, over four years, there are 2 × 2 × 2 × 2 = 16 possible outcomes. There are five favorable outcomes: Cancellations in years 1, 2, 3, and 4, years 1, 2, and 3, years 1, 2, and 4, years 1, 3, and 4, or years 2, 3, and 4. number of favorable outcomes P(event ) = number of possible outcomes 5 16 = 31.25% P(at least 3 years of cancellations out of 4) = So, the theoretical probability is of having at least three 5 years of four with cancellations is , or 31.25%. 16 Alternatively, Example 3 could have been solved using the following method. P (1, 2, 3, 4) = P(1) • P( 2) • P(3) • P( 4) 1 1 1 1 1 = • • • = 2 2 2 2 16 P (1, 2, 3, not 4) = P(1) • P( 2) • P(3) • P( not 4) 1 1 1 1 1 • • • = 2 2 2 2 16 P (1, 2, not 3, 4) = P(1) • P( 2) • P( not 3) • P( 4) = 1 1 1 1 1 • • • = 2 2 2 2 16 P (1, not 2, 3, 4) = P(1) • P( not 2) • P(3) • P( 4) = 1 1 1 1 1 • • • = 2 2 2 2 16 306 Big Ideas Math Red Accelerated Worked-Out Solutions = 1 1 1 1 1 • • • = 2 2 2 2 16 5 1 So, the theoretical probability is 5 = , or 31.25%. 16 16 Exercise 1: The events are independent, and 1 P(correct guess) = . 2 P( 4 correct guesses) = P(correct guess) • P(correct guess) • P(correct guess) • P(correct guess) 1 1 1 1 • • • 2 2 2 2 1 = 16 1 The theoretical probability is , or 6.25%. 16 = P( rain on Tuesday) = 0.2 = P (not 1, 2, 3, 4) = P( not 1) • P( 2) • P(3) • P( 4) Exercise 2: The events are independent, and P( winning ) = 0.7. P( three wins) = P( winning ) • P( winning ) • P( winning) = (0.7)(0.7)(0.7) = 0.343 The theoretical probability is 0.343 or 34.3%. Exercise 3: The events are independent. P(cancellation ) = 0.4 = 2 5 P( no cancellation ) = 0.6 = 3 5 P(1, 2, 3, 4) = P(1) • P( 2) • P(3) • P( 4) 2 2 2 2 16 • • • = 5 5 5 5 625 P(1, 2, 3, not 4) = P(1) • P( 2) • P(3) • P( not 4) = 2 2 2 3 24 • • • = 5 5 5 5 625 P(1, 2, not 3, 4) = P(1) • P( 2) • P( not 3) • P( 4) = 2 2 3 2 24 • • • = 5 5 5 5 625 P(1, not 2, 3, 4) = P(1) • P( not 2) • P(3) • P( 4) = 2 3 2 2 24 • • • = 5 5 5 5 625 P (not 1, 2, 3, 4) = P( not 1) • P( 2) • P(3) • P( 4) = = 3 2 2 2 24 • • • = 5 5 5 5 625 So, the theoretical probability is 16 24 24 24 24 112 + + + + = = 17.92%. 625 625 625 625 625 625 When you increase the number of trials in a simulation, the experimental probability approaches the theoretical probability of the event that you are simulating. Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 Study Help 9. A multiple of 3 was rolled 21 + 23 = 44 times. Available at BigIdeasMath.com. Quiz 10.1–10.5 1. There are 2 red butterflies. So, choosing a red butterfly can occur in 2 ways. The probability of rolling a multiple of 3 is 2. There are no brown butterflies. So, choosing a brown butterfly can occur in 0 ways. 3. There are 4 butterflies that are not blue. So, choosing a not blue butterfly can occur in 4 ways. 4. P(green ) = = number of green paper clips total number of paper clips 3 , 10 number of yellow paper clips total number of paper clips 5 5 1 = = 6+3+ 4+ 2+5 20 4 The probability of choosing a yellow paper clip is 1 , 4 or 25%. 6. P( not yellow ) = = number of not yellow paper clips total number of paper clips 6+3+ 4+ 2 15 3 = = 6+3+ 4+ 2+5 20 4 The probability of choosing a paper clip that is not yellow 3 is , or 75%. 4 7. P( purple) = 10. A 2 or a 3 was rolled 22 + 21 = 43 times. P( 2 or 3) = number of times a 2 or a 3 rolled 43 = total number of rolls 120 43 , or about 120 35.8%. or 30%. = 11 , or about 30 36.7%. The probability of rolling a 2 or a 3 is 6 6 3 = = 6+3+ 4+ 2+5 20 10 The probability of choosing a green paper clip is 5. P( yellow ) = number of times multiple of 3 rolled 44 11 P( multiple of 3) = = = total number of rolls 120 30 number of purple paper clips total number of paper clips 0 = = 0 6+3+ 4+ 2+5 11. The number of times a number less than 7 was rolled is 120. number of times less than 7 rolled total number of rolls 120 = 120 =1 P(less than 7) = The probability of rolling a number less than 7 is 1, or 100%. 12. Event 1: There are 4 possible types. Event 2: There are 3 possible colors. 4 × 3 = 12 There are 12 possible kinds of calculators. 13. Event 1: There are 4 possible destinations. Event 2: There are 2 possible lengths. 4×2 = 8 There are 8 possible vacations. 14. P( black ink ) = number of black ink pens 2 = total number of pens 5 The probability of randomly choosing a black pen is 2 , or 40%. 5 The probability of choosing a purple paper clip is 0, or 0%. 8. The total number of rolls is 18 + 22 + 21 + 16 + 20 + 23 = 120. P( 4) = number of times 4 rolled 16 2 = = total number of rolls 120 15 The probability of rolling a 4 is Copyright © Big Ideas Learning, LLC All rights reserved. 2 , or about 13.3%. 15 Big Ideas Math Red Accelerated Worked-Out Solutions 307 Chapter 10 15. P(first is blue) = 6. no; You can have a large sample that is not representative 2 5 P(second is blue) = 1 4 P( A and B ) = P( A) • P( B after A) P( both blue) = P( blue) • P( blue after blue) 2 1 = • 5 4 1 = 10 The probability that you and your friend both choose a 1 blue pen is , or 10%. 10 Section 10.6 10.6 Activity (pp. 440 –441) 1. a. Population: The students in a school; Sample: The students in a math class b. Population: The grizzly bears in a park; Sample: The grizzly bears with GPS collars in a park c. Population: All quarters in circulation; Sample: 150 quarters d. Population: All books in a library; Sample: 10 fiction books in a library 2. a. no; Not every student in your school is equally likely of being selected. Most of the responses may be playing or listening to music. b. no; Not every student in your school is equally likely of being selected. Not all students may read the school newspaper. c. yes; Every student in your school is equally likely of being selected. d. no; Not every student in your school is equally likely of being selected. You are only surveying students from a certain grade. 3. a. not valid; Residents that call into the radio show most likely have very strong opinions and not everyone may listen to the radio. b. not valid; The reporter only talked to 2 residents. The size of the sample is not large enough to draw any valid conclusions. c. valid; You talked to a good amount of residents that are randomly selected and your conclusion is reasonable based on your results. 4. Sample answer: A sample accurately represents a population when the sample is large enough, random, and not just a certain portion of the population. 5. Check students’ work. 308 Big Ideas Math Red Accelerated Worked-Out Solutions of a population. Sample answer: You survey residents about a new power plant being built but you only survey residents who will live close to the power plant. This could result in a large sample that is not representative of residents in a town. 10.6 On Your Own (pp. 442–443) 1. C; The sample is representative of the population. 2. The sample that surveys every 5th student on an alphabetical list of eighth graders is unbiased because every eighth grader is equally likely of being selected. Sampling 15 band members is biased because it does not represent the entire eighth grade, and band members are more likely to listen to music. 3. No, firefighters are more likely to support the new sign. students in survey students in school (two or more movies) (two or more movies) 4. = total surveyed students in school 24 n = 75 1200 384 = n So, about 384 students in the school watch two or more movies each week. 10.6 Exercises (pp. 444 –445) Vocabulary and Concept Check 1. You would survey a sample instead of a population because samples are easier to obtain. 2. You should make sure the people surveyed are selected at random and are representative of the population, as well as making sure your sample is large enough. Practice and Problem Solving 3. The population is the residents of New Jersey. The sample consists of the residents of Ocean County. 4. The population is all the cards in a deck. The sample consists of the 4 cards drawn from the deck. 5. biased; The sample is not selected at random and is not representative of the population because students in a band class play a musical instrument. 6. unbiased; The sample is representative of the population, selected at random, and large enough to provide accurate data. 7. biased; The sample is not representative of the population because people who go to the park are more likely to think that the park needs to be remodeled. 8. The sample is representative of the population, selected at random, and large enough to provide accurate data. So, the sample is unbiased and the conclusion is valid. Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 9. The sample is not representative of the population because people going to the baseball stadium are more likely to support building a new baseball stadium. So, the sample is biased and the conclusion is not valid. Fair Game Review 20. 10. Sample A is not large enough to provide accurate data. Sample B is a large sample, so Sample B is better for making a prediction. 11. Sample B is not representative of the population because the population consists of pencils from all the machines. Sample A is representative of the population, so Sample A is better for making a prediction. p 100 p = 100 p = 100 = = 100 • p 100 = p So, 30% of 60 is 18. 12. students in school ( pizza ) students in survey (pizza) = number of students in survey number of students in school a w 18 60 3 10 3 100 • 10 30 21. n 58 = 125 1500 696 = n So, there are about 696 students in the school whose favorite food is pizza. a w 98 w 98 w 980 p 100 70 = 100 7 = 10 = 7w = 140 = w 13. Because the population size is very large, you would So, 70% of 140 is 98. survey a sample. 14. Because the population size is very small, you would 22. survey the population. 15. Because the population size is very large, you would survey a sample. Number surveyed who said yes Student tickets bought 16. = Total surveyed Students in school 12 210 = 72 n n = 1260 There are about 1260 students in the school. 17. Not everyone has an email address, so the sample may not be representative of the entire population. Sample answer: When the survey question is about technology or which email service you use, the sample may be representative of the entire population. 18. a. Sample answer: The person could ask “Do you agree with the town’s unfair ban on skateboarding on public property?” b. Sample answer: The person could ask “Do you agree that the town’s ban on skateboarding on public property has made the town quieter and safer?” 19. Sample answer: no; 75% of the students in the sample said that they plan to attend college. Because 75% of 900 is 675, the counselor’s prediction was too high. The counselor included students that replied “maybe,” increasing the number to 80% of 900, or 720 students. Copyright © Big Ideas Learning, LLC All rights reserved. a w 30 w 30 w 600 p 100 15 = 100 3 = 20 = 3w = 200 = w So, 30 is 15% of 200. 23. a w a 500 a 500 1000a p 100 0.6 = 100 6 = 1000 = 3000 = a = 3 So, 3 is 0.6% of 500. 1 Bh 3 1 = ( 4)(6)(5) 3 = 40 24. A; V = So, the volume of the pyramid is 40 cm3. Big Ideas Math Red Accelerated Worked-Out Solutions 309 Chapter 10 10.6 Extension (pp. 446 –447) Activity 1 Step 5: Number of students who prefer pop music: 10 + 13 + 8 + 10 + 9 = 50 Number of students surveyed: 20 + 20 + 20 + 20 + 20 = 100 Step 1: Number you surveyed Students in school who prefer pop who prefer pop = Total surveyed Students in school Number surveyed Students in school who prefer pop who prefer pop = Total surveyed Students in school 10 n = 20 840 420 = n 50 n = 100 840 420 = n So, there are 420 students who prefer pop music. Step 2: Number Kevin surveyed Students in school who prefer pop who prefer pop = Total surveyed Students in school 13 n = 20 840 546 = n So, there are 546 students who prefer pop music. Using Kevin’s results, this inference is more than the inference in Step 1. Step 3: Number Steve surveyed Students in school who prefer pop who prefer pop = Total surveyed Students in school So, there are 420 students who prefer pop music when all five samples are combined. Practice 1. a. Check students’ work. make a more accurate prediction by increasing the number of random samples. Activity 2 Step 1: 6+8+6+6+7+ 4 + 10 + 8 + 7 + 8 70 Mean 1: = =7 10 10 10 + 4 + 4 + 6 + 8 +6 + 7 + 12 + 8 + 8 73 Mean 2: = = 7.3 10 10 8 n = 20 840 336 = n 10 + 9 + 8 + 6 + 5 +8 + 6 + 6 + 9 + 10 77 Mean 3: = = 7.7 10 10 Number Laura surveyed Students in school who prefer pop who prefer pop = Total surveyed Students in school 4+8+4+4+5 +4 + 4 + 6 + 5 + 6 50 Mean 4: = =5 10 10 10 n = 20 840 420 = n 6 + 8 + 8 + 6 + 12 +4 + 10 + 8 + 6 + 12 80 Mean 5: = =8 10 10 Number Ming surveyed Students in school who prefer pop who prefer pop = Total surveyed Students in school 9 n = 20 840 378 = n Mean 6: 10 + 10 + 8 + 9 + 16 +8 + 7 + 12 + 16 + 14 110 = = 11 10 10 4+5+6+6+4 +5 + 6 + 6 + 4 + 4 50 Mean 7: = =5 10 10 Steve: 336 students prefer pop music. Laura: 420 students prefer pop music. 16 + 20 + 8 + 12 + 10 +8 + 8 + 14 + 16 + 8 120 Mean 8: = = 12 10 10 Ming: 378 students prefer pop music. Step 4: Sample answer: The greatest is 546 students. The least is 336 students. 420 is the median and the mode of the data. So, use the inference of 420 students. b. Check students’ work. c. Check students’ work. Sample answer: Yes, you can Step 2: 3 4 5 6 7 8 9 10 11 12 13 Mean hours worked each week Step 3: Sample answers: The actual mean number of hours probably lies within the interval 6 to 9.5 hours (the box). So, about 7.5 hours is a good estimate. The mean of the entire data set is 7.875. So, the estimate is close. 310 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 Activity 3 b. Both distributions are approximately symmetric. Step 1: Check students’ work. c. For Male Students in Grade 8: Step 2: Check students’ work. Sample answer: Because the actual percent of students is 70%, students can say that they expect the number of red peanuts in their samples to be between 60% –80%, or 55% –85%, or 65% –75%, etc. Step 3: Check students’ work. Practice 7+9+8+7 1 1 +8 2 2 1 +10 + 6 + 6 + 8 + 8 2 1 1 1 +8 + 9 + 11 + 7 + 8 2 2 2 = 123 = 8.2 Mean: 15 15 From part (a): 2. a. Median: 8 0 10 20 30 40 50 60 70 80 90 100 Percent that prefer water Mode: 8, 8 b. Sample answer: The actual percent of student-athletes that prefer water over a sports drink probably lies within the interval 50% to 70% (the box). So, about 60% is a good estimate. 60 + 70 + 60 + 50 + 80 +70 + 30 + 70 + 80 + 40 610 Mean: = = 61 10 10 The mean of the data is 61%. So, the estimate is close. 3. First order all the data to find the median of each sample. Step 1: Medians are: 7, 7.5, 8, 4.5, 8, 10, 5, and 11. Step 2: 3 4 5 6 7 8 9 10 11 12 13 Median hours worked each week Step 3: Sample answers: The actual median number of hours probably lies within the interval 6 to 9 hours (the box). So, about 7.5 is a good estimate. The median of the data is 8. So, the estimate is close. 1 2 Range: 11 − 6 = 5 Interquartile range (IQR): 9 − 7.5 = 1.5 Mean Absolute Deviation (MAD): Find the mean of how far each data point deviates from the mean of 8.2. 1.2 + 0.8 + 0.2 + 0.7 + 0.3 +1.8 + 2.2 + 1.7 + 0.2 + 0.2 +0.3 + 0.8 + 2.8 + 0.7 + 0.3 14.2 MAD: = ≈ 0.95 15 15 For Male Students in Grade 6: 1 1 1 6+5 +6+6 +7 2 2 2 1 1 1 +8 + 7 + 5 + 5 + 5 2 2 2 1 1 +6 + 7 + 4 + 6 + 6 93 2 2 = = 6.2 Mean: 15 15 From part (a): Median: 6 4. Check students’ work. Mode: 6 5. The more samples you have, the more accurate your inferences will be. By taking multiple random samples, you can find an interval where the actual measurement of a population may lie. 1 1 Range: 8 − 4 = 4 2 2 Interquartile range (IQR): 7 − 5.5 = 1.5 Mean Absolute Deviation (MAD): Find the mean of how far each data point deviates from the mean of 6.2. Section 10.7 10.7 Activity (pp. 448 –449) 0.2 + 0.7 + 0.2 + 0.3 + 1.3 +2.3 + 0.8 + 0.7 + 1.2 + 0.7 +0.3 + 0.8 + 1.7 + 0.2 + 0.2 11.6 MAD: = ≈ 0.77 15 15 1. a. Sample answer: Male students (8th Grade) Male students (6th Grade) Mean Median Mode Shoe sizes 4 5 6 7 8 9 5 6 7 8 9 10 11 12 13 4 5 6 7 8 9 10 11 12 13 Copyright © Big Ideas Learning, LLC All rights reserved. Interquartile Range (IQR) Mean Absolute Deviation (MAD) 10 11 12 Shoe Size 4 Range Male Students in Eighth-Grade Class 8.2 8 8, 8 2 5 1.5 0.95 Male Students in Eighth-Grade Class 6.2 6 6 4 1.5 0.77 1 Male students (8th grade) Male students (6th grade) Big Ideas Math Red Accelerated Worked-Out Solutions 311 Chapter 10 d. The mean, median, and one of the modes of the shoe sizes for male students in the eighth-grade class are each 2 more than the mean, median, and mode of the shoe sizes for male students in the sixth-grade class. e. yes; The IQRs are the same. The range and MAD are slightly greater for the male students in the eighthgrade class. So, the shoe sizes for the male students in the eighth-grade class are slightly more spread out than the shoe sizes for the male students in the sixthgrade class. 2. a. male students: symmetric; female students: skewed left; yes; Sample answer: The data set for the female students completely overlaps the data set for the male students. The overlaps between the centers and between the extreme values are shown. Male students Female students f. yes; Sample answer: The smallest shoe size of the male students in the eighth-grade class is about the same as the mean shoe size of the male students in the sixth-grade class. The largest shoe size of the male students in the sixth-grade class is about the same as the mean shoe size of the male students in the eighth-grade class. 5 6 7 8 9 10 11 12 13 5 6 7 8 9 10 11 12 4 5 6 7 8 9 10 11 12 Hours of sleep Male students Female students Hours of sleep b. male students: symmetric; female students: Shoe Size 4 4 Male students (8th grade) symmetric; yes; Sample answer: The overlaps between the centers and between the extreme values are shown. Heights (inches) 4 5 6 7 8 9 10 11 12 13 Male students (6th grade) Male students g. no; Sample answer: You could have the following data 56 57 58 59 60 61 62 63 64 65 sets. 1 1 1 1 1 Tigers: 8 , 8 , 9 , 9 , 9 , 10, 10, 11, 12 2 2 2 2 2 1 Bobcats: 6, 7, 7, 7, 7 , 8, 8, 8, 9 2 yes; Sample answer: From the double box-andwhisker plot, you know that at least one girl on the Bobcats has a shoe size of 9. You also know that at 1 least one girl on the Tigers has a shoe size of 8 . 2 Female students 56 57 58 59 60 61 62 63 64 65 Heights (inches) Male students 56 57 58 59 60 61 62 63 64 65 Female students 56 57 58 59 60 61 62 63 64 65 c. 8:00 P.M. Class: symmetric; 10:00 A.M. Class: skewed right; no; The oldest person in the 8:00 P.M. class is 40. The youngest person in the 10:00 A.M. class is 42. 3. Sample answer: You can compare the measures of center, the measures of variation, the shapes of the distributions, and the overlap of the two distributions. 10.7 On Your Own (pp. 450 –451) 1. In part (a), Candidate A’s mean increases by 30 to 114, but the MAD is unchanged. In part (b), the quotient is 56 = 3.5. So, the difference in the means is now now 16 3.5 times the MAD. The number is greater, indicating less overlap in the data. 312 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 2. No, the sample size is too small to make a conclusion b. The water snakes have greater measures of center about the population. because the mean, median, and mode are greater. The water snakes also have greater measures of variation because the interquartile range and mean absolute deviation are greater. 10.7 Exercises (pp. 452–453) Vocabulary and Concept Check 1. When comparing two populations, use the mean and the MAD when each distribution is symmetric. Use the median and the IQR when either one or both distributions are skewed. 4. a. Team A: median = 3, IQR = 4 − 2 = 2 Team B: median = 7, IQR = 8 − 6 = 2 The variation in the goals scored is the same, but Team B usually scores about 4 more goals per game. 2. There will probably be little or no visual overlap of the data. The core (center) portions of the data are too far apart. b. Practice and Problem Solving 3. a. Garter snake lengths ordered: 15, 18, 21, 22, 24, 24, 25, 26, 28, 30, 32, 35 Measures of center: 5. a. Class A: median = 90, IQR = Q3 − Q1 = 95 − 82.5 = 12.5 15 + 18 + 21 + 22 +24 + 24 + 25 + 26 300 +28 + 30 + 32 + 35 Mean = = = 25 in. 12 12 Class B: median = 80, IQR = Q3 − Q1 = 85 − 75 = 10 The variation in the test scores is about the same, but Class A has greater test scores. Median = 24.5 in. Mode = 24 in. Measures of variation: Range = 35 − 15 = 20 in. IQR = Q3 − Q1 = 29 − 21.5 = 7.5 in. 10 + 7 + 4 + 3 +1 + 1 + 0 + 1 52 +3 + 5 + 7 + 10 MAD = = ≈ 4.33 in. 12 12 Water snake lengths ordered: 21, 24, 25, 27, 30, 32, 32, 34, 35, 37, 40, 41 Measures of center: 21 + 24 + 25 + 27 +30 + 32 + 32 + 34 378 +35 + 37 + 40 + 41 Mean = = = 31.5 in. 12 12 median for Team B − median for Team A 4 = = 2 IQR for Team A 2 median for Team B − median for Team A 4 = = 2 IQR for Team B 2 The difference in the medians is 2 times the IQR. b. median for Class A − median for Class B 10 = = 0.8 IQR for Class A 12.5 median for Class A − median for Class B 10 = =1 IQR for Class B 10 The difference in the medians is 0.8 to 1 times the IQR. 6. a. Volleyball Game Attendance: 112 + 75 + 49 + 95 + 88 +54 + 84 + 93 + 85 + 106 +127 + 74 + 62 + 98 + 88 1720 +68 + 117 + 132 + 53 + 60 Mean = = = 86 20 20 Mode = 32 in. 26 + 11 + 37 + 9 + 2 +32 + 2 + 7 + 1 + 20 +41 + 12 + 24 + 12 + 2 392 +18 + 31 + 46 + 33 + 26 MAD = = = 19.6 20 20 Measures of variation: Basketball Game Attendance: Median = 32 in. Range = 41 − 21 = 20 in. IQR = Q3 − Q1 = 36 − 26 = 10 in. 10.5 + 7.5 + 6.5 + 4.5 +1.5 + 0.5 + 0.5 + 2.5 61 +3.5 + 5.5 + 8.5 + 9.5 MAD = = ≈ 5.08 in. 12 12 202 + 176 + 163 + 190 + 141 +186 + 173 + 152 + 184 + 155 +181 + 207 + 169 + 198 + 219 3700 +188 + 214 + 228 + 195 + 179 Mean = = = 185 20 20 17 + 9 + 22 + 5 + 44 +1 + 12 + 33 + 1 + 30 +4 + 22 + 16 + 13 + 34 354 +3 + 29 + 43 + 10 + 6 MAD = = = 17.7 20 20 The variation in the attendances is about the same, but basketball has a greater attendance. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 313 Chapter 10 b. The difference in the means is 99. This is about 5.1 14. B; times the MAD for the volleyball game attendance and 5.6 times the MAD for the basketball attendance. percent of increase = 125 − 100 100 25 = 100 = 25% 7. The value for Exercise 6(b) is the greatest. This means = that the attendances have the least overlap of the data sets in Exercises 4–6. 8. a. Sports magazine: 9 + 21 + 15 + 14 + 25 +26 + 9 + 19 + 22 + 30 190 Mean = = = 19 10 10 10 + 2 + 4 + 5 + 6 58 +7 + 10 + 0 + 3 + 11 MAD = = = 5.8 10 10 The number of students in the marching band increased by 25%. Quiz 10.6–10.7 1. Sample A is not large enough to make a prediction. Sample B is large, so Sample B is better for making a prediction. Political magazine: 31 + 22 + 17 + 5 + 23 +15 + 10 + 20 + 20 + 17 180 Mean = = = 18 10 10 13 + 4 + 1 + 13 + 5 +3 + 8 + 2 + 2 + 1 52 MAD = = = 5.2 10 10 The mean and MAD for the sports magazine are close to the mean and the MAD for the political magazine. However, the sample size is small and the variability is too great to conclude that the number of words per sentence is about the same. b. The sample means vary much less than the sample 2. biased; The sample is not selected at random and is not representative of the population because students on the basketball team use the gymnasium regularly when practicing. 3. The sample is representative of the population, selected at random, and large enough to provide accurate data. So, the sample is unbiased and the conclusion is valid. 4. students in survey (aquarium) students in school (aquarium) = total surveyed students in school 16 n = 60 720 192 = n numbers of words per sentence. c. The number of words per sentence is generally greater in the political magazine than in the sports magazine. 9. a. Check students’ work. Experiments should include taking many samples of a manageable size from each grade level. This will be more doable if the work of sampling is divided amongst the whole class, and the results are pooled together. About 192 students would choose the aquarium. 5. a. Team A: median = 14, IQR = Q3 − Q1 = 22 − 6 = 16 Team B: median = 32, b. Check students’ work. The data may or may not IQR = Q3 − Q1 = 36 − 20 = 16 support a conclusion. The variation in the points is the same, but Team B has greater scores. Fair Game Review 10. 11. new amount − original amount original amount b. 2 3 4 5 6 7 8 −6 −5 −4 −3 −2 −1 0 −1 0 1 4 5 6 −1.6 12. −5 −4 −3 13. −2 median for Team B − median for Team A 18 = = 1.125 IQR for Team A 16 median for Team B − median for Team A 18 = = 1.125 IQR for Team B 16 The difference in the medians is 1.125 times the IQR. 2.5 0 1 2 3 314 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 6. a. Camp A: mean = 15, 5. a. There are 8 sections with a number greater than 0. So, spinning a number greater than 0 can occur in 8 ways. 20 MAD = =1 20 b. Camp B: mean = 13, MAD = 20 =1 20 The variation in the ages is the same, but Camp A has a greater age. b. mean for Camp A − mean for Camp B 2 = = 2 MAD for Camp A 1 mean for Camp A − mean for Camp B 2 = = 2 MAD for Camp B 1 The difference in the means is 2 times the MAD. Chapter 10 Review 1. a. There are 2 sections with a 1. So, spinning a 1 can occur in 2 ways. b. greater than 0 not greater than 0 1 green, 1 purple, 2 blue, 2 orange, 2 green, 3 orange, 3 blue, 3 purple none The favorable outcomes of the event are spinning 1 green, 1 purple, 2 blue, 2 orange, 2 green, 3 orange, 3 blue, and 3 purple. 6. a. There are 5 sections with a number less than 3. So, spinning a number less than 3 can occur in 5 ways. b. less than 3 not less than 3 1 green, 1 purple, 2 blue, 2 orange, 2 green 3 orange, 3 blue, 3 purple The favorable outcomes of spinning a number less than 3 are 1 green, 1 purple, 2 blue, 2 orange, and 2 green. 1 not 1 1 green, 1 purple 2 blue, 2 orange, 2 green, 3 purple, 3 blue, 3 orange number of even numbers total number of numbers 3 = 6 1 = 2 7. P(even ) = The favorable outcomes of the event are spinning 1 green and 1 purple. 2. a. There are 3 sections with a 3. So, spinning a 3 can occur in 3 ways. b. 3 not 3 3 purple, 3 blue, 3 orange 1 green, 1 purple, 2 blue, 2 orange, 2 green The favorable outcomes of the event are spinning 3 purple, 3 blue, and 3 orange. 3. a. There are 5 sections with an odd number. So, spinning an odd number can occur in 5 ways. b. odd not odd 1 green, 1 purple, 3 orange, 3 blue, 3 purple 2 blue, 2 orange, 2 green The favorable outcomes of the event are spinning 1 green, 1 purple, 3 orange, 3 blue, and 3 purple. 4. a. There are 3 sections with an even number. So, spinning an even number can occur in 3 ways. b. even not even 2 blue, 2 orange, 2 green 1 green, 1 purple, 3 orange, 3 blue, 3 purple The favorable outcomes of the event are spinning 2 blue, 2 orange, and 2 green. Copyright © Big Ideas Learning, LLC All rights reserved. The experimental probability of rolling an even number is 1 , or 50%. 2 8. P(3) = number of times 3 spun 16 8 = = total number of spins 70 35 The experimental probability of spinning a 3 is 8 , or 35 about 22.9%. 9. The total number of times an odd number was spun is 14 + 16 + 13 = 43. number of times an odd number spun 43 P(odd ) = = total number of spins 70 The experimental probability of spinning an odd number 43 is , or about 61.4%. 70 10. The number of times not 5 was spun is 14 + 12 + 16 + 15 = 57. P( not 5) = number of times not 5 spun 57 = total number of spins 70 The experimental probability of not spinning a 5 is 57 , 70 or about 81.4%. Big Ideas Math Red Accelerated Worked-Out Solutions 315 Chapter 10 11. The number of times a number greater than 3 was spun is 15 + 13 = 28. 18. Coin number of times greater than 3 spun 28 2 P(greater than 3) = = = total number of spins 70 5 Outcome 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 HH1 HH2 HH3 HH4 HH5 HH6 HT1 HT2 HT3 HT4 HT5 HT6 TH1 TH2 TH3 TH4 TH5 TH6 TT1 TT2 TT3 TT4 TT5 TT6 H T number of blue sections 2 1 = = total number of sections 8 4 The theoretical probability of spinning blue is 13. P(1) = Cube H The experimental probability of spinning a number 2 greater than 3 is , or 40%. 5 12. P( blue) = Coin 1 , or 25%. 4 H T number of "1" sections 3 = total number of sections 8 The theoretical probability of spinning a 1 is T 3 , or 8 37.5%. 14. P(even ) = number of even sections 5 = total number of sections 8 P(event ) = The theoretical probability of spinning an even number 5 is , or 62.5%. 8 15. P( 4) = P(T, T, even ) = 1 , or 8 19. P( A and B) = P( A) • P( B) P( blue and tails) = P( blue) • P( tails) 12.5%. 4 1 • 7 2 2 = 7 = number of even sections total number of sections 2 8 = n 3 n = 12 16. P (even ) = The probability of choosing a blue tile and flipping tails 2 is , or about 28.6%. 7 There are 12 sections on the spinner. 17. Event 1: Choosing a bracelet (6 possible) Event 2: Choosing a necklace (15 possible) 6 × 15 = 90 There are 90 ways you can wear one bracelet and one necklace. 3 1 = 24 8 So, the probability of flipping two tails and rolling an 1 even number is , or 12.5%. 8 number of "4" sections 1 = total number of sections 8 The theoretical probability of spinning a 4 is number of favorable outcomes number of possible outcomes 20. P( A and B) = P( A) • P( B) P(G and tails) = P(G ) • P( tails) 1 1 • 7 2 1 = 14 = The probability of choosing the letter G and flipping tails 1 is , or about 7.1%. 14 316 Big Ideas Math Red Accelerated Worked-Out Solutions Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 P( A and B) = P( A) • P( B after A) 21. P(green and blue) = P(green ) • P( blue after green ) 2 4 • 7 6 4 = 21 = The probability of choosing a green tile and then a blue 4 tile is , or about 19.0%. 21 P( A and B) = P( A) • P( B after A) 22. P( red and vowel) = P( red) • P( vowel after red ) 1 2 = • 7 6 1 = 21 The probability of choosing a red tile and then a vowel is 1 , or about 4.8%. 21 23. biased; The sample is not selected at random and is not representative of the population because students in the biology club like biology. 24. a. Class A: median = 88, IQR = Q3 − Q1 = 91 − 85 = 6 b. yellow not yellow yellow, yellow, yellow, yellow, yellow red, blue, red, green, blue The favorable outcomes of choosing not yellow are red, blue, red, green, and blue. 3. Event 1: 5 possible SPF’s Event 2: 3 possible types 5 × 3 = 15 There are 15 possible sunscreens. 4. The total number of rolls is 12 + 18 + 14 + 17 + 16 + 13 = 90. The total number of times a 1 or a 2 was rolled is 12 + 18 = 30. number of times a 1 or 2 was rolled 30 1 P(1 or 2) = = = total number of rolls 90 3 The experimental probability of rolling a 1 or a 2 is 5. The total number of times an odd number was rolled is IQR = Q3 − Q1 = 94 − 85 = 9 number of times odd number was rolled 42 7 P(odd ) = = = total number of rolls 90 15 median for Class B − median for Class A 3 = = 0.5 IQR for Class A 6 median for Class B − median for Class A 3 = ≈ 0.3 IQR for Class B 9 The difference in the medians is about 0.3 to 0.5 times the IQR. 1. a. There is 1 green game piece. So, choosing green can occur 1 way. green not green green yellow, red, blue, yellow, red, yellow, yellow, blue, yellow The favorable outcome of choosing green is green. Copyright © Big Ideas Learning, LLC All rights reserved. 1 , or 3 about 33.3%. 12 + 14 + 16 = 42. Chapter 10 Test b. choosing not yellow can occur in 5 ways. Class B: median = 91, In general Class B has greater scores than Class A. Class A has less variation than Class B. b. 2. a. There are 5 game pieces that are not yellow. So, The experimental probability of rolling an odd number is 7 , or about 46.7%. 15 6. The total number of times a number not 5 was rolled is 12 + 18 + 14 + 17 + 13 = 74. number of times a number not 5 was rolled total number of rolls 74 = 90 37 = 45 P( not 5) = The experimental probability of not rolling a 5 is 37 , or 45 about 82.2%. Big Ideas Math Red Accelerated Worked-Out Solutions 317 Chapter 10 number of even-numbered sections number of sections 4 = 9 7. P(even ) = 12. a. Show A: median = 45, IQR = Q3 − Q1 = 50 − 40 = 10 Show B: median = 35, IQR = Q3 − Q1 = 40 − 25 = 15 4 The probability of spinning an even number is , or 9 about 44.4%. b. 8. P( A and B ) = P( A) • P( B ) P(1 and 2) = Show B generally has a younger audience and more variation in ages than Show A. 1 1 1 • = 9 9 81 The probability of spinning a 1 and then a 2 is 1 , 81 or about 1.2%. median for Show A − median for Show B 10 = =1 IQR for Show A 10 median for Show A − median for Show B 10 = ≈ 0.7 IQR for Show B 15 The difference in the medians is about 0.7 to 1 times the IQR. Chapter 10 Standards Assessment 1. C; Only D.C. United with 3 votes, the Minnesota Lynx 2 1 = 16 8 1 P(second is bishop) = 15 9. P(first is bishop) = P( A and B ) = P( A) • P( B after A) P( both bishop) = P( bishop) • P( bishop after bishop) 1 1 • 8 15 1 = 120 = The probability of choosing a bishop first and then 1 another bishop is , or about 0.8%. 120 10. P(first is king) = 1 16 P(second is queen ) = with 4 votes, the New York Knicks with 5 votes, and possibly the other 6 votes are non-Florida teams. So, it is unlikely, but not impossible that this team member’s favorite professional sports team is not located in Florida. students that voted Sunday 6 1 1 = = 2. or 0.2; P(Sunday) = total number 30 5 5 of students 2 1 = of the way 12 6 around the circle (the circumference). 3. G; In 2 hours, the hour hand travels The circumference of the circle is 22 C = 2π r ≈ 2 (84) = 528 mm. 7 So, the hour hand travels 1 15 P( A and B) = P( A) • P( B after A) P( king and queen ) = P( king) • P(queen after king) 1 1 • 16 15 1 = 240 = The probability of choosing a king first and then a queen 1 is , or about 0.4%. 240 11. biased; The sample size is too small and students standing in line are more likely to say they prefer to buy their lunches at school. 318 Big Ideas Math Red Accelerated Worked-Out Solutions 4. C; 1 (528) = 88 mm. 6 16 p = 40 27 16 • 27 = 40 • p 432 = 40 p 432 40 p = 40 40 10.8 = p 5. H; The area of one face-off circle is A = π r 2 ≈ (3.14)(15) = 706.5 ft 2 . 2 So, the total area of the 5 face-off circles is 5(706.5) = 3532.5 ft 2 . Copyright © Big Ideas Learning, LLC All rights reserved. Chapter 10 6. 1 2 1 , or 0.0625, or 6.25%; P( yellow ) = = 16 8 4 P( both yellow ) = P( yellow ) • P( yellow ) 1 1 • 4 4 1 = 16 = The probability of spinning two yellows is 1 , or 16 0.0625, or 6.25%. 7. C; Area of base = 6 • 6 = 36 in.2 Area of lateral face = 1 • 6 • 8 = 24 in.2 2 S = area of base + areas of lateral faces = 36 + 24 + 24 + 24 + 24 = 132 in.2 8. H; percent of increase = new amount − original amount original amount 15 − 6 6 9 = 6 = 1.5 = = 150% 9. Part A: The events are independent because the outcome of the first roll does not affect the second roll. Part B: even not even 2, 4, 6 1, 3, 5 Each roll has 3 favorable outcomes and 6 possible outcomes. Part C: P( A and B) = P( A) • P( B) 3 3 • 6 6 1 1 = • 2 2 1 = 4 P( both even ) = The probability of rolling two even numbers is 1 , or 4 0.25, or 25%. Copyright © Big Ideas Learning, LLC All rights reserved. Big Ideas Math Red Accelerated Worked-Out Solutions 319
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