Name
Reteaching
13-2
Using Unit Rates
A unit rate is a special ratio that compares one quantity to one unit of
another quantity. You can use unit rates to solve proportions.
Write a proportion.
Use d for dollars earned.
$100
$d
____
5 __
 
4h
7h
Find the unit rate.
Divide the first term by
the second term.
Think: Find an equal ratio
with 1 as the second term.
$100 4 4 5 $25
25
100 4 4 5 __
______
$25
.
The unit rate is ___
1h
Multiply by the unit rate.
$25
___
3 7h 5 $175
h
1
444
Think: Find an equal ratio.
25 3 7 5 ___
175
_____
7
137
$100
$175
So, ____
5 ____
. Geraldo will earn $175 when he works 7 hours.
4h
7h
Use unit rates to solve each proportion. Estimate to check reasonableness.
4
g
30g
1. ________
5 ____
2 kg
15 kg
2g
___
kg
Unit Rate:
200
120 mi = ________
mi
2. _____
3 gal
5 gal
23254
$24
$ 80
____
5 ________
Unit Rate:
Multiply:
4.
3 wk
10 wk
____
40 mi
gal
20
8 in. = ________
in.
3. ____
2 wk
5 wk
Unit Rate:
____
4 in.
wk
40355200Multiply: 435520
200 stamps
56 oz 5 ______
900 stamps
64 oz
________
6. ________ 5 ____________
Multiply:
5.
7 packs
8 packs
2 rows
9 rows
7. Wes used 49 quarts of oil when he changed the oil in 7 cars.
Complete and solve the proportion to find how many quarts of oil
he would use to change the oil in 20 cars, assuming that all cars
need the same quantity of oil.
49 quarts
_______
7 cars 5
7 quarts
x quarts
140 quarts
______
______
________
5
5
1 car
20 cars
20 cars ; 140 quarts
8. Writing to Explain A café served 180 pickles with 60 sandwiches.
If the ratio of sandwiches to pickles is always constant, explain
how you can use unit rates and proportions to find how many
pickles are needed to serve 32 sandwiches.
96pickles;Sampleanswer:Writeandsolvetheproportion
xpickles
180pickles
______________
.
__________
5
60sandwiches
32sandwiches
28 Topic 13
© Pearson Education, Inc. 6
Reteaching 13-2
Geraldo earns $100 for 4 hours of work. If he works 7 hours at the
same rate of pay, how much will he earn?