Page 278 - Algebra 1

L E S S O N Solving Percent Problems 42
Warm Up
New Concepts
1. Vocabulary Two equivalent ratios form a . (31)
Solve the equation.
2. 3x + 8 = 32 3. -6y - 7 = 29
(23)
(23)
4. A team’s ratio of wins to losses in football games is 5 to 4. If the team wins
(36)
25 games, how many games did the team lose?
5. The ratio of white marbles to black marbles is 7 to 10. There are
(36)
136 marbles in the bag. How many marbles are white?
A percent is a ratio that compares a number to 100. For example, 50% is the 50
ratio _100 . There are three components that form a percent statement: the whole is the total amount; the percent is a rate that quantifies an amount measured with respect to the whole; the percentage is a number that represents a percent of the whole.
25% of 20 is 5.
Percent Whole Percentage
If two of the components are known, then the third component can be determined.
Using an Equation to Find a Percentage
a. What number is 25% of 50 ?
SOLUTION
c = 0.25 · 50 Change the percent to its decimal form. = 12.5 Multiply the percent by the whole.
Example
1
25 _1 _1 _
Check 25% is 100 or 4 . So, (4 )(50) = 12.5.
Online Connection www.SaxonMathResources.com
n = 1.25 · 64 = 80
Change the percent to its decimal form.
Multiply the percent by the whole.
125 _5 _5 _
b. What number is 125% of 64? SOLUTION
Check 125% is 100 or 4. So, (4)(64) = 80
Lesson 42 263