Calculating payments, interest, and APR on auto loan.  After careful comparison shopping, Noah Griffin decides to buy a new Toyota Camry. With some options added, the car has a price of $23,558—including plates and taxes. Because he can’t afford to pay cash for the car, he will use some savings and his old car as a trade-in to put down $3,558. Noah plans to finance the rest with a $20,000, 60-month loan at a simple interest rate of 4 percent.

a. What will his monthly payments be?

b. How much total interest will Noah pay in the first year of the loan? 

c. How much interest will Noah pay over the full (60-month) life of the loan?

d. What is the APR on this loan?