You plan to purchase an $100,000 house using a 15-year mortgage obtained from your local bank. The mortgage rate offered to you is 4.5 percent. You will make a down payment of 10 percent of the purchase price. a. Calculate your monthly payments on this mortgage. b. Calculate the amount of interest and, separately, principal paid in the 80th payment. c. Calculate the amount of interest and, separately, principal paid in the 110th payment. d. Calculate the amount of interest paid over the life of this mortgage.