1. EXAMPLE 2 Finding a Base Marc received 273, or 35%, of the votes in the student council election. How many students voted in the election? Student Council a = p % b Write percent equation. Substitute 273 for a and 35 for p. 273 = 35% b Write 35% as a decimal. 780 = b Divide each side by 0.35. 273 = 0.35 b 780 students voted in the election. ANSWER

2. EXAMPLE 3 Finding Simple Interest You deposit $500 in a savings account that pays a simple interest rate of 2.5% per year. How much interest will you earn after 18 months? Savings I = Prt Write formula for simple interest. = (500)(0.025)(1.5) Substitute values. 18 months = 1.5 years. =18.75 Multiply. You will earn $18.75 in interest. ANSWER

3. EXAMPLE 1 GUIDED PRACTICE for Examples 2 and 3 Solve using the percent equation. 6.4 is 62.5% of what number? 4. 10.24 ANSWER

4. EXAMPLE 1 GUIDED PRACTICE for Examples 2 and 3 Solve using the percent equation. 15 is what percent of 120 ? 5. 12.5% ANSWER

5. EXAMPLE 1 GUIDED PRACTICE for Examples 2 and 3 What If? Suppose the simple interest rate in Example 3 is 3.5%. How much interest will you earn after 24 months? 6. You will earn $35 in interest. ANSWER