What is the annual rate of return for $8,000 investment if in five years it grows to $12,500. Assuming the growth occurred in 6 years and then in 8 years, recalculate the rate of return for these two scenarios. I have the following answers: 5 yrs = 9%, 6 years = 8% and 8 years = 6 %. How do I recalculate rate of return for the two scenarios