1. Using Equations to Solve Percent Problems
Objective:
Learn to use equations to solve problems involving percents.

2. One way to solve percent problems is by writing an equation.
When writing an equation you must remember the following:
The word of means multiply ( × )
The word is means equals ( = )
Rewrite percents as decimals.
what number stands for the variable N
What percent stands for the variable P

3. Example 1: What percent of 48 is 15 ? Steps: 3. Divide
P × 48 = Write the equation.
Use inverse operations.
3. Divide
P = Write the decimal as a
P = % percent.

4. Example 2: 12 % of what number is 9? 0.12 × N = 9 0.12 0.12 N = 75
N = 75
Steps:
Write the equation.
Convert the percent to a decimal.
Use the inverse operation.
Cancel
Divide
Write answer

5. Example 3:
What number is 25% of 200?
N = 25% × 200
N = × 200
N =
Steps:
Write the equation.
Change the percent to a decimal.
Multiply

6. Your Example: What percent of 78 is 39? 55% of 985 is what number?
30% of what number is 45?

7. Homework: Solve each problem.
What percent of 70 is 22?
9% of 600 is what number?
11% of what number is 36?
95% of 40 is what number?
89% of what number is 178?
6. What percent of 72 is 67? % of 58 is what number? 8. What percent of 65 is 30? 9. 18% of what number is 12? % of 50 is what number?