Percent & Practice Exam Part 1
First for Percentages
The term “Percent” is a very specific ratio. It is equal to the number of
Items per 100. 10% = 10 per cent = 10 per 100.
 Let’s watch a quick video about Percent (Video 1)
Using a proportion to help calculate percentages can make the following questions easier to answer.
1) Using what you know about the proportion equation, calculate 12/56 as a percent.
On Power Point
This works because it creates the equation you would use to figure out the answer.
2) John pays $70 for a new coat, which is 35% of the original cost. What was the original Cost?
Solve using a proportion:
On Power Point
Solve using the percent equation:
On Power Point
3) A dress has been marked down 25% and now sells for $27. What was the original cost?
Solve using a proportion:
On Power Point
Solve using the percent equation:
On Power Point
Now lets take a look at some more types of percent problems:
4) What is 40% of 90?
36
5)Express 75% as a decimal
.75
6) What percent of 25 is 5?
20
7) What percent of 250 is 20?
8%
8) Amy charged $500 worth of merchandise on her credit card. When she got her bill, which did not
include any interest, she paid $100. During the next month she charged another $70 worth of
goods. When she got her next bill she was charged 2% interest on her entire unpaid balance. How
much interest was she charged?
((500—100) + 70)*.02 = interest charged
((400)+70)*.02
470 * .02
$9.40 = interest charged
9) There are 600 students, the ratio of female students to male students is 7:5. 20% of the female
students are blond, 45% of the remaining students have brown hair, and 15% of the students who
do not have blond or brown hair have red hair. How many female students have a hair color other
than blond, brown, or red?
#girl students = use ratio of 7:5 to calculate what part of 600 you are working with = 350 girls
Of 350 Girls 20% have blond hair = 350 * .20 = 70 girls with blond hair
Of 280 remaining girls (350-70) 45% have brown hair = 280 * .45 = 126 girls with brown hair
Of 154 remaining girls (280—126) 15% have red hair = 154 * .15 = 23.1
350—(70 + 126 + 23.1) = # female students with hair color other than blond, brown or red
350—(219.1) = 130.9
10) Peebles is having an extreme close-out sale. A remote control helicopter is only $6.00. If the
helicopter’s original price was cut in half and then marked down an additional 5% every day since
the sale started, if the sale started 5 days ago (not including the day the price was cut in half), what
was the original price?
This type of question will not actually appear on the exam, please disregard
$6.00 = x - [x/2 - (x/2*.05) - ((x/2*.05)*.05) - (((x/2*.05)*.05) *.05) - ((((x/2*.05)*.05)
*.05) *.05) - (((((x/2*.05)*.05) *.05) *.05) *.05)
Exactly Like the Exam (Take Home):
These questions are just like the type of questions you will see on the exam.
1) Donna drives her delivery van 800 miles in 3 days. At this rate, how far will she drive in
15 days?
800 * 15 = 3X
12,000 = 3 x
4000 = x
2) According to the 1980 census, the population of Los Angeles County was approximately 7.5 million. In 1990
the population was approximately 9 million. Find the percent of increase of the population.
3) The temperature in Minneapolis was 4 degrees on December 3. In the next 3 days, the temperature
dropped 2 degrees, then dropped 5 degrees, and then dropped 10 degrees. What was the temperature on
December 6?
4 -2 -5 - 10 = -13
4) In a hospital, 36 ml of a drug are mixed with 1.6 liters of water to form a drug-water solution.
Following this ratio, how many ml of water would be needed to mix with 6.2ml of drug?
Convert liters of water to ml --> 1.6 liters = 1600 ml
36ml * x = 1600ml * 6.2ml
36 ml * x = 9920 ml
Divide both sides by 36ml
X = 9920 ml / 36 ml
X = 275.56
5) Find .6% of 36
.216
6) 360 students are in the gym for a basketball game. 50% of the students are
Freshmen, 30% are Sophomores, after excusing the Freshmen and Sophomores,
75% of the remaining students were juniors, once the juniors were excused how
many students remained in the gym?
# of freshman = 360 * .50 = 180
# of Sophomores = 360 * .30 = 108
# of Juniors = (360 - 180 - 108) * .75 = 54
# of Seniors = 360 - 180-108-54 = 18
There were 18 students in the gym
7) Simplify:
8) Simplify:
1/30
9) Maryland has a sales tax of 6%. Delaware has no sales tax at all. Would it be cheaper to buy a sweater
for $79 in Maryland or $84 in Delaware?
Maryland: $79 * 1.06 = $83.74
Delaware: $84
It would be cheaper to buy the sweater in Maryland.