Problem of the Day

1
Problem of the Day There are 3 bags of flour for
every 2 bags of sugar in a freight truck. A bag
of flour weighs 60 pounds, and a bag of sugar
weighs 80 pounds. Which part of the trucks
cargo is heavier, the flour or the sugar?
flour
2
A rate is a comparison of two quantities that
have different units.
Read as 90 miles per 3 hours.
90 miles 3 hours
Rate
3
Unit rates are rates in which the second(bottom)
quantity is 1. To find a unit rate divide the
numerator by the denominator
90 3
30 1

30 miles, 1 hour
unit rate
or 30 mi/h
4
Unit price is a unit rate used to compare costs
per item.
5
Additional Example 3A Finding Unit Prices to
Compare Costs
Pens can be purchased in a 5-pack for 1.95 or a
15-pack for 6.20. Which is the better buy?
Divide the price by the number of pens.
price for package number of pens
1.95 5
?

0.39
price for package number of pens
6.20 15

?
0.41
The better buy is the 5-pack for 1.95.
6
Additional Example 3B Finding Unit Prices to
Compare Costs
Jamie can buy a 15-oz jar peanut butter for 2.19
or a 20-oz jar for 2.78. Which is the better
buy?
Divide the price by the number of ounces.
2.19 15

?
0.15
2.78 20

?
0.14
The better buy is the 20-oz jar for 2.78.
7
Try This Example 3A
Golf balls can be purchased in a 3-pack for 4.95
or a 12-pack for 18.95. Which is the better buy?
Divide the price by the number of balls.
price for package number of balls
4.95 3
?

1.65
price for package number of balls
18.95 12
?

1.58
The better buy is the 12-pack for 18.95.
8
Insert Lesson Title Here
Lesson Quiz
1. At a family golf outing, a father drove the
ball 285 ft. His daughter drove the ball 95 ft.
Express the ratio of the fathers distance to his
daughters in simplest terms. 2. Find the unit
price of 6 stamps for 2.22. 3. Find the unit
rate of 8 heartbeats in 6 seconds. 4. What is the
better buy, a half dozen carnations for 4.75 or
a dozen for 9.24? 5. Which is the better buy,
four pens for 5.16 or a ten-pack for 12.90?
31
0.37 per stamp
? 1.3 beats/s
a dozen
They cost the same.