Practice Percent Change in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

Percent change measures how much a quantity has increased or decreased relative to its original value, calculated as new−originaloriginal×100%\frac{\text{new} - \text{original}}{\text{original}} \times 100\%.

If a price goes from $50 to $60, the change is $10. Compared to the original $50, that's 1050=20%\frac{10}{50} = 20\% increase.

Showing a random 20 of 50 problems.

Example 1

medium
A stock rises 20% from \$50, then the next day the new price falls 20%. What is the final price?

Example 2

easy
A price rises from 50to50 to 60. What is the percent change?

Example 3

medium
A gadget falls from $120\$120 to $90\$90. What is the percent decrease?

Example 4

hard
After three consecutive 10%10\% annual raises, a salary becomes $66,550\$66{,}550. What was the starting salary?

Example 5

easy
A test score falls from 25 to 20 points. What is the percent decrease?

Example 6

hard
A population grows by 5%5\% per year. After how many full years will it exceed double its original size? (Use approximation.)

Example 7

medium
After a 30%30\% increase, a price becomes $65\$65. What was the original price?

Example 8

medium
After a 40%40\% discount, an item costs $36\$36. What was the original price?

Example 9

medium
A population grew from 5,0005{,}000 to 8,5008{,}500. What is the percent increase?

Example 10

hard
A stock price rises by 20%20\% one year and falls by 20%20\% the next year. If it started at $100\$100, what is the final price and the overall percent change?

Example 11

medium
A stock rose 50%50\%, then fell 50%50\%. What is the net percent change from the start?

Example 12

challenge
A coat costs $120\$120 after a 20% markup on cost. The store then offers 10% off the marked price. What does a customer pay?

Example 13

medium
A class had 2020 students; now it has 2424. Express the change as a percent.

Example 14

medium
Sales tax is 8%8\%. The total paid is $54\$54. What was the price before tax?

Example 15

easy
A book's price rises from $10\$10 to $12\$12. What is the percent change?

Example 16

medium
A town's population grew from 12,00012{,}000 to 15,00015{,}000. What is the percent increase?

Example 17

hard
A price increases by 10%10\% in January, then by another 20%20\% in February. What is the overall percent increase?

Example 18

medium
A $80\$80 jacket is on sale for $68\$68. What is the percent discount?

Example 19

medium
A quantity increased by 50% to become 90. What was the original value?

Example 20

easy
A bag once held 8080 candies; now it has 100100. What is the percent increase?
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