Math: Percent Increase and Decrease
Finding percent change in real-world situations
Math: Percent Increase and Decrease
Finding percent change in real-world situations
Math - Grade 6-8
- 1
A backpack costs $40. The price increases by 15%. What is the new price?
Find 15% of 40 first, then add it to the original price.
The increase is 15% of $40, which is $6. The new price is $40 + $6 = $46. - 2
A video game originally costs $60. It is on sale for 25% off. What is the sale price?
The discount is 25% of $60, which is $15. The sale price is $60 - $15 = $45. - 3
A school club had 80 members last year. This year it has 100 members. What is the percent increase?
Use percent change = amount of change divided by original amount.
The increase is 100 - 80 = 20 members. The percent increase is 20 divided by 80, which equals 0.25 or 25%. - 4
A plant was 50 centimeters tall. After a week without enough water, it was 45 centimeters tall. What is the percent decrease?
The decrease is 50 - 45 = 5 centimeters. The percent decrease is 5 divided by 50, which equals 0.10 or 10%. - 5
The population of a town increased from 12,000 to 13,800. What was the percent increase?
Subtract first to find the amount of change.
The increase is 13,800 - 12,000 = 1,800 people. The percent increase is 1,800 divided by 12,000, which equals 0.15 or 15%. - 6
A jacket costs $75. During a sale, the price is decreased by 20%. What is the sale price?
The discount is 20% of $75, which is $15. The sale price is $75 - $15 = $60. - 7
A phone battery charge increased from 30% to 75%. What is the percent increase based on the original charge?
The original amount is 30, not 100.
The increase is 75 - 30 = 45 percentage points. The percent increase is 45 divided by 30, which equals 1.5 or 150%. - 8
A recipe uses 2 cups of flour. A baker increases the recipe by 50%. How many cups of flour are needed now?
The increase is 50% of 2 cups, which is 1 cup. The new amount is 2 + 1 = 3 cups of flour. - 9
A bike was priced at $240. After a discount, it costs $180. What is the percent decrease?
Divide the discount by the original price.
The decrease is $240 - $180 = $60. The percent decrease is 60 divided by 240, which equals 0.25 or 25%. - 10
A test score increased from 72 points to 90 points. What is the percent increase?
The increase is 90 - 72 = 18 points. The percent increase is 18 divided by 72, which equals 0.25 or 25%. - 11
A sweater is on sale for 30% off. The original price is $50. A student says the sale price is $35. Is the student correct? Explain.
Check by finding 30% of the original price.
The student is correct. The discount is 30% of $50, which is $15, and $50 - $15 = $35. - 12
A movie theater sold 320 tickets on Friday and 400 tickets on Saturday. What was the percent increase in tickets sold?
The increase is 400 - 320 = 80 tickets. The percent increase is 80 divided by 320, which equals 0.25 or 25%. - 13
A number is decreased by 10%. The original number is 150. What is the new number?
A 10% decrease means subtract 10% of the original amount.
The decrease is 10% of 150, which is 15. The new number is 150 - 15 = 135. - 14
The price of a concert ticket increased by 12%. The original price was $85. What is the new price?
The increase is 12% of $85, which is $10.20. The new price is $85 + $10.20 = $95.20. - 15
A class had 28 students. After several students moved away, the class had 21 students. What was the percent decrease?
Use the original number of students as the denominator.
The decrease is 28 - 21 = 7 students. The percent decrease is 7 divided by 28, which equals 0.25 or 25%.