Lesson 3.7- Percent of Change, pg. 160

Goals: To find percents of increase and decrease. To solve problems involving percents of change.

Vocabulary

Percent of change: an increase or decrease expressed as a percent.

Percent of increase: the new number is greater than the original number.

Percent of decrease: the new number is less than the original number.

Percent of Change Formula

Percent of Change: difference in the amounts

original amount

Or Percent of change = New value-Original V

Original Value

Multiply the answer by 100 to get the percent of change.

Ex. 1: State whether each percent of change is a percent of decrease or increase. Then find the percent of change.

1. original: 32

new: 40

2. original: 20

new: 4

You TRY!!!!

3. original: 72

new: 36

4. original: 45

new: 50

Ex. 2: Find the missing value.1. The price a used-book store pays to buy

a book is $5. The store sells the book for 28% above the price that it pays for the book. What is the selling price of the $5 book?

Ex. 3: Find the total price of each item.

1. Software: $39.50

Sales tax: 6.5%

2. Compact disc: $15.99

sales tax: 5.75%

Ex. 4: Find the discounted price of each item.

1. jeans: $45.00

discount: 25%

2. book: $19.95

discount: 33%

Ex. 5: Find the final price of each

1. lamp: $120.00

discount: 20%

tax: 6%

2. camera: $58.00

discount: 25%

tax: 6.5%

Application1. In 1987, the United States had 2 million

active-duty military personnel. By 2000, there were only 1.4 million active-duty military personnel. What was the percent of decrease?

2. In order for a food to marked “reduced fat,” it must have at least 25% less fat than the same full-fat food. If one ounce of reduced fat chips has 6 grams of fat, what is the least amount of fat in one ounce of regular chips?