What is the present worth of the following series of payments? (a) $3,000 at the end of

Question:

What is the present worth of the following series of payments?
(a) $3,000 at the end of each six-month period for 10 years at 6% compounded semiannually.
(b) $4,000 at the end of each quarter for 12 years at 8% compounded quarterly.
(c) $2,200 at the end of each month for four years at 9% compounded monthly.