An alumnus wishes to provide an income for her university of $8,000 per year forever. If the funds can be deposited by the university at 4%, what sum must she donate?

ans : $200,000

An individual arranges to repay a $10,000 loan in 15 equal annual installments. Interest is 4%. After the 10th payment she wished to pay the balance in a lump sum. Assuming no penalty, how much does she owe?

ans: $4,004

What is the present worth of $40,000 end of year payments for 20 years at $15% compounded continuously?

ans: $234,920

I know these are the correct answers, but I am not sure how to do the work to get them please help