How can we use the concept:
Find the percent of increase from 25 to 80.
We know this is an increase because the number is increasing.
First find the difference of the two numbers that are being compared.
(Highest minus the Lowest)
80-25=55
Divide your difference by the original number and then multiply by 100
55/25 x 100% =220% increase
Find the percent of decrease 20 to 10
We know this is a decrease because the numbers are decreasing.
Find the difference (highest minus the lowest)
20-10=10
Divide the difference by the original number and then multiply by 100.
10/20 x 100% =50%
Sample Math Problems
Question
The staff at a company went from 40 to 28. What is the percent of decrease?
Solution
We know this is a decrease because the numbers are decreasing.
Find the difference (highest minus the lowest)
40-28=12
Divide the difference by the original number and then multiply by 100.
12/40 x 100% =30%
Question
A school increased it’s enrollment from 280 students to 400 students. What is the percent of increase?
Solution
We know this is an increase because the numbers are increasing.
Find the difference (highest minus the lowest)
400-280=120
Divide the difference by the original number and then multiply by 100.
120/400 x 100% =30%
Question
A wooden board started at 8 feet but Tim sawed 6 feet off. What was the percent of decrease?
Solution
8-6=2
2/8 x 100=25%
Question
The candy price went from $0.50 to $0.75. Find the percent of increase. Round to the nearest tenth.
Solution
0.75 - 0.50 = 0.25
0.25/0.75 x 100 = 33.3%
