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
rkhelp.html
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.