Percent of ChangePercent of ChangePRE-ALGEBRA LESSON 6-8PRE-ALGEBRA LESSON 6-8

6-8

Write these fractions to the nearest tenth of a percent.

a. b. 65255

42 52

25.5% 80.8%

Percent of ChangePercent of ChangePRE-ALGEBRA LESSON 6-8PRE-ALGEBRA LESSON 6-8

6-8

The __________________ is the percent a quantityIncreases or decreases from its original amount

Vocabulary

Find the percent of increase from 8 to 9.6.

Percent of ChangePercent of ChangePRE-ALGEBRA LESSON 6-8PRE-ALGEBRA LESSON 6-8

amount of increase = 9.6 – 8 = 1.6

= 0.2 = 20%

The percent of increase from 8 to 9.6 is 20%.

percent of increase = amount of increase

original amount

=1.68

Quick Check

6-8

In a given year, Hillsboro had a total of 7.5 in. of rain by

March 1 and a total of 22.5 in. by July 1. Find the percent of

increase from 7.5 to 22.5.

Percent of ChangePercent of ChangePRE-ALGEBRA LESSON 6-8PRE-ALGEBRA LESSON 6-8

amount of increase = 22.5 – 7.5 = 15

= 2 = 200%

The percent of increase from March 1 to July 1 was 200%.

percent of increase = amount of increase

original amount

=157.5

Quick Check

6-8

Find the percent of decrease from 1,250 to 1,120.

Percent of ChangePercent of ChangePRE-ALGEBRA LESSON 6-8PRE-ALGEBRA LESSON 6-8

amount of decrease = 1,250 – 1,120 = 130

= 0.104 = 10.4%

percent of decrease = amount of decrease

original amount

= 1301,250

Quick Check

6-8

Percent of ChangePercent of ChangePRE-ALGEBRA LESSON 6-8PRE-ALGEBRA LESSON 6-8

Solve.

1. Find the percent of increase from 22 to 63.

2. Find the percent of decrease from 6.3 to 2.2.

3. A surgeon performed 62 operations in 1991. He performed 342 in 2001. Find the percent of increase.

186.4%

451.6%

65.1%

6-8