Cheyenne deposited $200 in a bank account earning continuously compounded interest. After 10 years, she closed the account and withdrew the entire balance, which totaled $364.42. What was her annual interest rate? Rounded to the nearest dollar, how much would Cheyenne have received if she had left the money in the account for 15 years? 20 years? Use the continuously compounded interest formula, , where is the ending amount, is the principal or initial amount, is a constant, is the annual interest rate expressed as a decimal, and is the time in years.

Determine values for the continuously compounded interest formula.

Substitute the known values into the formula and solve for the annual interest rate, .

Determine how much money Cheyenne would have received if she had left the money in the account for 15 years.

Determine how much money Cheyenne would have received if she had left the money in the account for 20 years.

This applet is provided by Walch Education as supplemental material for the CCGPS Advanced Algebra program. Visit www.walch.com for more information on our resources.