In order to buy a car, you borrow $17,500 from a friend at 15%/year compounded monthly for 4 years. You plan to repay the loan with 48 equal monthly payments. ( I have already solved part a, b, and c just need part d)

a) How much are the monthly payments? --> 487.03 per month

b) How much interest is in the 23rd payment? --> 134.43

c) What is the remaining balance after the 37th payment? --> 4976.32

d) 3 & 1/2 years after borrowing the money, you decide to pay off the loan. You have not yet made the payment due at that time. What is the payoff amount for the loan?