Problem #5: You want to buy a car that costs $21,000. The dealer wants a 10% down payment and quotes a 15% APR for a 72-month loan. (a) What will be your monthly payment if the payment is made at the end of each month from the day you buy the car? (b) What will be your monthly payment if you tell the dealer that you will not make any down payment, but you will make your payments at the beginning of every month starting today