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

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 = 1.5years.

=18.75 Multiply.

You will earn $18.75 in interest.

ANSWER

EXAMPLE 1GUIDED PRACTICE for Examples 2 and 3

Solve using the percent equation.

6.4 is 62.5% of what number?4.

10.24ANSWER

EXAMPLE 1GUIDED PRACTICE for Examples 2 and 3

Solve using the percent equation.

15 is what percent of 120?5.

12.5%ANSWER

EXAMPLE 1GUIDED 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