Answer: 18%
Explanation:
The payments that your friend will make are an annuity as they are constant. This means that the loan amount of $15,000 is the present value of the annuity.
To find the rate of return, use the factor tables.
Present value of annuity = Annuity * Present value interest factor of annuity, 14 years, ?%
15,000 = 3,000 * Present value interest factor of annuity, 14 years, ?%
Present value interest factor of annuity, 14 years, ?% = 15,000 / 3,000
Present value interest factor of annuity, 14 years, ?% = 5.0
Go to the present value of annuity factor table and find out what interest rate intersects with 14 periods such that the factor is 5.0.
That rate is 18%.
Rate of return is therefore 18%.