You plan to purchase a $280,000 house using either a 25-year mortgage obtained from your local savings bank with a rate of 7.10 percent, or a 15-year mortgage with a rate of 6.20 percent. You will make a down payment of 25 percent of the purchase price. a. Calculate the amount of interest and, separately, principal paid on each mortgage. What is the difference in interest paid? b. Calculate your monthly payments on the two mortgages. What is the difference in the monthly payment on the two mortgages?