Transcript Slide 1
4-1 Ratios to Rates
Ratio
a comparison of two quantities by division
5:8
5/8
5 to 8
Rate
a ratio that compares quantities measured
in different units
5 seconds: 8 feet
5 snails / $8
5 miles to 8 gallons
Unit Rate
is the rate for one unit of a given quantity
5 miles: 1 second
$5 / 1 snail
5 gallons of water to 1 gallon of lemon juice
Ch. 4-1 Ratios and Rates
Example 1: Write a ratio for the following below by using the hearts and
stars.
a.) hearts to stars
4:3
b.) stars to all figures
3:7
c.) all figures to hearts
7:4
Example 2: Write each ratio in simplest form.
a.) 50 m. : 30 m.
b.) 16 cm. : 8 cm.
5 m. : 3 m.
2 cm. : 1 cm.
c.) 32 in. : 4 in.
8 in. : 1 in.
Example 3: Find each unit rate below.
a.) A team finished the 200 lap Indiana Little race in about 2.07 hours. Find
the unit rate of laps per hour.
200
96 .6
2.07
Laps per hour
b.) Find the unit rate for 52 deliveries in 8 hours.
52
6 .5
8
Deliveries per hour
Example 4: Find the unit cost for each bottle. Which size is the better buy?
$2.99 for 64 oz.
2.99
.0467
64
= $ .05/oz.
$1.59 for 12 oz.
1.59
.1325
12
= $ .13/oz.
Therefore the 64 oz. bottle has the lowest unit cost and is the better buy.
You try one:
Which is the better buy: a 20 oz box of cereal for $4.29 or a 12 oz. box of
the same cereal for $3.59?
The 20 oz. box
http://my.hrw.com/math06_07/nsmedia/homework_help/msm2/msm2_ch05_01_homewo
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Homework
Pg 162
#1-7 all do in one box
#8-26 evens only
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 father’s distance to his daughter’s
in simplest terms.
3:1
2. Find the unit price of 6 stamps for $2.22. $0.37 per stamp
3. Find the unit rate of 8 heartbeats in 6 seconds. 1.3 beats/s
4. What is the better buy, a half dozen carnations for $4.75 or a dozen for
$9.24? a dozen
5. Which is the better buy, four pens for $5.16 or a ten-pack for $12.90?
They cost the same.