Answer:
The interest rate on Mason's account is 3.9%
Explanation:
1. Let's review the information provided to us to answer the question correctly:
Mason's account balance after 21 years = $ 1,637.10
Initial deposit = $ 900
Time of the investment = 21 years
2. What is the simple interest on the account?
Let's use the simple interest formula, this way:
FV = P * (1 + rt)
FV = Future Value P = Initial deposit
r = Interest rate t = time of the investment
Replacing with the real values, we have:
1,637.10 = 900 + (1 + 21r)
1,637.10 = 900 + 18,900r
18,900r = 1,637.10 - 900
18,900r = 737.10
r = 737.10/18,900
r = 0.039
The interest rate on Mason's account is 3.9%