On your tenth birthday, you received $300 which you invested at 4.5 percent interest, compounded annually. Your investment is now worth $756. How old are you today?
A) Age 20
B) Age 31
C) Age 30
D) Age 23
E) Age 21

Question

Quizplus · Accepted Answer

To find the age, use the formula for compound interest: $ A = P(1 + r)^t $. Here, $ A = 756 $, $ P = 300 $, and $ r = 0.045 $. Solving for $ t $, we get $ t \approx 21 $. Since the investment started on your tenth birthday, you are now 31 years old.

On Your Tenth Birthday, You Received $300 Which You Invested