Percent Change
Subtract the original price from the new
price to find the amount of increase.
Percent change is the ratio of the change to the
original price expressed as a percent.
A $25 shirt is on sale for $20. What is the percent
decrease in price?
To find the percent decrease, use a proportion.
Let drate of decrease
$5 100 $25d 20 d
So 20%
The decrease in price is 20%.
Last month the skateboard that Joe wanted cost $40. This month
the skateboard costs $50. What is the percent increase in price?
To find the percent increase, use a proportion.
Let irate of increase
i
i
i0.2525%
The increase in price is 25%.
Find the percent decrease or increase.
- $45 decreased by $9 2. $85 decreased by $42.50 3. 120 decreased by 54
- 828 decreased by 289.8 5. 316 decreased by 28.44 6. $32 increased by $8
- $62 increased by $18.60 8. 648 increased by 486 9. 153 increased by 15.3
Find the percent change. Explain whether it is a decrease or increase.
- from $346 to $269.88 11.from 1295 to 1036 12. from $1022 to $715.40
- from $525 to $603.75 14.from 3950 to 4937.5 15. from $9696 to $12,895.68
$10
$40
$50 $40
$40
increase
original price
d
100
$5
$25
$25d
$25
$500
$25
d
100
$5
$25
d
100
$25 $20
$25
decrease
original price
$0 $20 $25
0% d 100%
Subtract the sale price from the original
price to find the amount of decrease.
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