Suppose $90,000 is invested into an account where interest is compounded annually. After 30 years the balance is $337,079. What was the interest rate as a percent?

Question

Interest Rate _________%

Answer 1

337079 = 90000(1 + r)³⁰. So, r = (337079/90000)^1/30 - 1 = 0.045 = 4.5%