27. Gotham billionaire Bruce Wayne has purchased a house for 102,000,000. Wayne makes a down payment of 2,000,000 and finances the rest of the mortgage through 15 years of end of month payments. The first payment is due exactly one month from today. The nominal rate of interest is 15% convertible monthly. The first 120 payments all contain 100,000 in principal. The last 60 payments go as follows. The 121st payment is X. Then each subsequent payment is 10% greater than the preceding one. a. Determine X. b. Determine the interest paid in the last five years of the loan. c. Determine the interest paid in the 13th year of the loan