A company deposited $11,500 into an investment fund at the beginning of every quarter for 7 years. It then stopped making deposits into the fund and allowed the investment to grow for 5 more years. The fund was growing at 3.75% compounded monthly.

a. What was the accumulated value of the fund at the end of 7 years ?

b. What was the accumulated value of the fund at the end of 12 years ?

c. What was the amount of interest earned over the 12-year period?