Hellpppp!!! these questions are tough I would love to check my answers

5] 5. A company estimates that it will have to replace a piece of equipment at a cost of $800, 000 in 5 years. 'Ib have this money available in 5 years, a. sinking fund is established by making equal monthly payments into an account paying 6.6% compounded monthly. (A) How much should each payment be? (B) How much interest is earned during the last year? . Some friends tell you that they paid $25,000 down on a new house and are to pay $525 per month for 30 years. If interest is 7.8% compounded monthly, (A) What was the selling price of the house? (B) How much interest will they pay in 30 years