At 8 percent interest per year, compounded annually, compute:

a. The present value of $100 to be received (24) twenty-four months from now;

b. The present value of $60 to be received at the end of each of the next (7) seven years;

c. The combined present value of $50 to be received (1) one year hence; $38 (2) two years hence; and $100 (5) five years hence, with no money being received in the third and fourth years.