I am having some trouble with this question...

An annuity providing a rate of return of 5.6% compounded quarterly was purchased for $27,000. The annuity pays $800 at the end of each quarter (except for a smaller final payment). a) How much of the sixteenth payment is interest? b) What is the principal portion of the thirty-third payment? c) What is the total interest in Payments 20 to 25 inclusive? d) How much will the principal be reduced by payments in the sixth year? e) What will be the final payment?