Future Value of an Annuity for Various Compounding Periods. I have been provided the answers but must show ALL WORK IN DETAIL AND FORMULAS.

Find the future values of the following ordinary annuites:

A-- FV of $400 each 6 months for 5 years at a nominal rate of 12%, compounded semiannually.

(Answer is 5, 272.32--show all work and formulas)

B--FV of $200 each 3 months for 5 years at a nominal rate of 12% compounded quartely

(Answer is 5, 374.07--show all work and formulas)

C--The annuities described in parts a and b have the same total amount of money paid into them during the 5-year period and both earn interest at the same nominal rate, yet the annuity in part b earns 101.75 more than the one in part a over 5 years. Why does this occur?--Please explain.