Using the appropriate PV table, compute the present value of the following amounts:
a. $ 25,000 payable at the end of each year for 10 years with 6% interest compounded annually.
b. $ 15,000 receivable at the beginning of each semiannual period for five years with 6% interest, compounded semiannually.
c. $ 5,000 payable at the beginning of the seventh, eighth, and ninth years at 7%, compounded annually.