What equal annual series of payment must be paid into a sinking fund to accumulate the following amounts?

1) $32,000 in 15 years at 8% compounded annually

2) $55,000 in 10 years at 6% compounded annually

3) $35,000 in 15 years at 7% compounded annually

4) $8,000 in 4 years at 11% compounded annually