Problem 3. Please use Excel to answer. Show a formula sheet and an answer sheet. (Simple Interest Loan) Suppose the 3-year loan of $18,000 at a 9% annual rate is a simple interest loan payable in 36 equal installments. (a.) Find the monthly payment for this loan. Explain how you determined the value. (b.) How much total interest is saved on an $18,000 loan using the amortized loan plan in Problem 2 instead of the simple interest plan?