Page 205 - Algebra 1

L E S S O N Using Rates, Ratios, and Proportions 31
Warm Up
New Concepts
1. Vocabulary The simplest form of _3 is _1 . When you a fraction,
(4)
62 you are writing it in simplest form.
Simplify. 2.2.3-3.6÷4-1.7
(4)
Solve.
4. 8x = 112
(21)
3. -0.4+1.3·4 __
(4) 0.5 - 5.1 ÷ 3 5. 2.5y = 62.5
(21)
A ratio is a comparison of two quantities using division. Examples: 2 boys to 3 girls 2 to 3, 2:3, _2
3
A rate is a ratio that compares quantities measured in different units.
Examples: 5 feet per 30 seconds 15 apples for $6.00 25,000 hits per month A unit rate is a rate whose denominator is 1. A unit price is the cost per unit. Examples: 55 miles per hour $2.50 per box
Finding Unit Rates
Which is the better buy: 5 cans of tuna for $4.95 or 6 cans for $5.75?
Find the unit price.
Find the unit price. Compare the unit prices.
Example
1
SOLUTION
Hint
When working with rates, usually you will see the words per, for, and each indicated by a forward slash (/).
1 mile per 2 minutes 1 mi/2 min
total cost = $4.95 = $0.99 per can ___
number of cans 6 $0.96 < $0.99
6 cans for $5.75 is the better buy.
Converting Rates
number of cans 5
total cost = $5.75 = 0.96 per can ___
Example
2
a. A bus driver drives at 30 miles per hour. What is the rate of the bus in miles per minute?
Multiply by a conversion factor. Cancel like units of measure.
SOLUTION
30 miles · 1 hour __
1 hour 60 minutes
130 miles · 1 hour ___
Online Connection www.SaxonMathResources.com
1 hour 2 60 minutes
If the driver drives 1 mi/2 min, then he drives _1 mi/min. 2
190 Saxon Algebra 1