You plan to purchase a $100,000 house using a 30-year mortgage obtained from your local credit union. The mort- gage rate offered to you is 8.25 percent. You will make a down payment of 20 percent of the purchase price. (LG 7-4) a. Calculate your monthly payments on this mortgage. b. Calculate the amount of interest and, separately, princi- pal paid in the 25th payment