MM255 Unit 1 Sample Problems
Sample Problem:
Round the following number, as indicated: 79,346,218.713
To round a number:
Look at the digit in the specified place, then look at the next digit to the right. If this digit is 5 or more add
one to the digit in the specified place and if this is less than 5 leave the number in the specified place
alone.
79,346,218.713 -- the 7 is in the ten millions place so it is the rounding digit
79,346,218.713 -- the 9 is to its right, so if it is 5 or larger round up (otherwise the rounding digit stays the
same)
Rounded to the ten millions place : 80,000,000
79,346,218.713 -- the 1 is in the hundredths place so it is the rounding digit
79,346,218.713 -- the 3 is to its right, so if it is 5 or larger round up (otherwise the rounding digit stays the
same)
Rounded to the nearest hundredth: 79,346,218.71
79,346,218.713 -- the 8 is in the ones place (nearest whole number is the same as the ones place) so it is the
rounding digit
79,346,218.713 -- the 7 is to its right even though the decimal is between we only worry about the numbers
for rounding, so if it is 5 or larger round up (otherwise the rounding digit stays the same)
Rounded to the nearest whole number: 79,346,219
79,346,218.713 -- the 6 is in the thousands place so it is the rounding digit
79,346,218.713 -- the 2 is to its right, so if it is 5 or larger round up (otherwise the rounding digit stays the
same)
Rounded to the thousands place: 79,346,000
Sample Problem:
Susan just bought a new condo. She would really like to work on her bedroom. She has decided to put up
a decorative border at the top of the room, all the way around the room and to stain the floor. The room is
22 feet by 25 feet.


The border can be purchased for $4.50 per yard ( 1 yard = 3 feet). You cannot purchase a part of a yard.
The stain is on sale for $23.50 a gallon. A gallon covers 200 square feet. You can only buy the stain by the
gallon.
Perimeter = 2 (length + width)
Area = length x width
a. Compute the perimeter of the room and then determine how much the border will cost her.
Answer: Perimeter = 2(length + width) = 2(22 + 25) = 94 feet
Since 1 yard = 3 feet, then 94feet/3 feet = 31.33 yards
She must purchase 32 yards of border. Since border costs $4.50 per yard, then 32 x $4.50 =
$144.00
b. How much will Susan need to spend on the stain for the floor?
Answer: Area = length x width = 22 feet x 25 feet = 550 square feet
Since 1 gallon of paint covers 200 square feet, she will need 550/200 = 2.75 gallons but she can
only purchase full gallons so she will need 3 gallons.
Cost = 3 gallons x $23.50 per gallon = $70.50
Sample Problem:
Tom attends a local community College. He will graduate shortly with an Associate’s degree in
Culinary Arts. He has considered furthering his education to get another degree in business in
hopes that the combined degrees will land him a job with a solid company that has opportunities
for growth.
Tuition for one semester costs $1650 (15 or more credit hours) or he can pay $115 per credit hour
if he takes less than 15 credit hours. It will cost him $8 per credit hour for student fees and there is
a $100 technology fee per semester. He needs to take 12 more 3 credit classes to complete his
degree in business. He will need to attend school for 4 more consecutive semesters (1 full year
plus 4 months) to complete this degree. Textbooks will cost $100 per class.
a. Tom is planning on taking 4 courses during his first 2 semesters and 2 courses during his last 2
semesters. How much will it cost him to get his second degree?
Answer:
There are 2 options available: If you take 15 or more credit hours you pay $1650 a semester and if
you don’t then you pay $115 per credit. Since Tom is taking 4 classes during his first 2 semesters,
he is then taking 4 x 3 credits per class or 12 credits for the first 2 semesters and then 2 classes
for the last 2 semesters so 2 x 3 = 6 credits for the last 2 semesters. Since in all four semesters he
will take fewer than 15 credits, he will have to use the option of paying per credit.
Cost for semester 1: 4 x 3 = 12 credits x $115 per credit = $1380 for the class
12 credits x $8 per credit for student fees = $96
Technology fee is $100 per semester
4 classes x $100 textbooks per class = $400
Total cost for semester 1 = $1380 + $96 + $100 + $400 = $1976
Semester 2 is the same as semester 1 so he will pay $1976 for semester 2 as well.
Cost for semester 3 : 2 x 3 = 6 credits x $115 per credit = $690 for the class
6 credits x $8 per credit for student fees = $48
Technology fee is $100 per semester
2 classes x $100 textbooks per class = $200
Total cost for semester 3 = $690+ $48 + $100 + $200 = $1038
Semester 4 is the same as semester 3 so he will pay $1038 for semester 4 as well.
Total cost of all 4 semesters = $1976 + $1976 + $1038 + $1038 = $6028
b. Tom needs to determine how much money he will need to borrow if he works 20 hours a week
at the local grocery store making $10 an hour. Tom will rent a room from a friend for $300 per
month and share the cost of groceries and utilities. Tom’s share will come to about $175 per
month. His other expenses will total about $400 per month. How much will he need to borrow
to complete his second degree in business after the 4 consecutive semesters. (For the sake of
simplicity, assume that a month contains exactly 4 weeks.)
Answer:
Costs: 16 months x ($300 for rent + $175 utilities and groceries + $400 other expenses) =
16 x ($875) = $14,000
Total costs : $14,000 + $6028= $20,028
Earnings: (16 months) 16 ( 4 * 20 * $10) = $12,800
Tom then needs to borrow: $20,028 - $12,800 = $7228
c. How many hours per week does he need to work in order to avoid taking out a loan? ( For the
sake of simplicity, assume that a month contains exactly 4 weeks.)
Since his total costs of living and college are $20,028, we can take $20,028 / ($10/hour * 4 hours/week *
16 weeks) = $20,028 / $640 = 31.3 hours or close to 32 hours a week.