Solve for the Present Value:

a. $27,000 payable at the end of each year for 19 years with 5% interest compounded annually.

b.$18,000 received at the beginning of each semiannual period for 5 years with 20% interest, compounded semiannually.

c. $1,000 payable at the beginning of the seventh, eighth, and ninth years at 10%, compounded annually.