1. 2-7 Percent of Change Percent of Change: what % something changes
Percent of increase: what % something goes up
Percent of decrease: what % something goes down

2. Find the percent of change
Original: 32
New: 40
Is this an increase or a decrease?
Goes up – so it is an increase
Use the proportion to solve.
8(100) = r(32)
800 = 32r
800/32 = 32r/32
25 = r or r = 25
25% increase

3. Try this one Original: 20 New: 4 Is it an increase or decrease?
Find the percent of decrease.
16(100) = 20r
1600 = 20r
1600/20 = 20r/20
80 = r or r = 80
80% decrease

4. Find the missing value
The price that a used bookstore 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 book?
(x-5)(100) = 5(28)
100x – 500 = 140
100x = 640
X = 6.40
Selling price = $6.40

5. Sales Tax
A meal for two at a restaurant (outside of Oregon) costs $ If the sales tax is 5%, what is the total price for the meal?
5% of $32.75 = 0.05 times 32.75 =
Round to 1.64
$ $1.64 =
$34.39

6. Discount
A dog toy is on sale for 20% off the original price. If the original price of the toy is $3.80, what is the discounted price?
20% of $3.80 = .20 times 3.80
= 0.76
Since it is a discount you subtract.
$ $0.76 =
$3.04

7. Try these – page 113 #1-9 odd 1. Decrease; 50% 3. Increase of 14%
miles
7. $16.91
9. $13.37
Homework #16 p even, 43-44