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Using Equations to Solve Percent Problems. Objective: Learn to use equations to solve problems involving percents. 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 ( × )
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Using Equations to Solve Percent Problems Objective: Learn to use equations to solve problems involving percents.
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
Example 1: • What percent of 48 is 15 ? Steps: P × 48 = 15 1. Write the equation. 48 48 2. Use inverse operations. 3. Divide P = 0.3125 4. Write the decimal as a P = 31. 25% percent.
Example 2: 12 % of what number is 9? 0.12 × N = 9 0.12 0.12 N = 75 Steps: • Write the equation. • Use the inverse operation. • Cancel • Divide • Write answer
Example 3: What number is 25% of 200? N = 25% × 200 N = 0.25 × 200 N = 50 • Steps: • Write the equation. • Change the percent to a decimal. • Multiply
Your Example: What percent of 78 is 39? 55% of 985 is what number? • 30% of what number is 45?
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? 7. 240% of 58 is what number? 8. What percent of 65 is 30? 9. 18% of what number is 12? 10. 40% of 50 is what number?