# How to Solve Problems Involving Percent Increase and Decrease in Common Core Algebra 1

## How to Solve Problems Involving Percent Increase and Decrease in Common Core Algebra 1

Percent increase and decrease are common concepts in algebra that involve finding how much a quantity changes relative to its original value. For example, if a shirt costs $20 and then goes on sale for $15, what is the percent decrease in the price of the shirt?

To answer this question, we need to use the following formula: