A 20-year mortgage is to be repaid with level annual end-of-year payments of 30,000 except that at both t = 10 and t = 20, the amount repaid is 150,000 (instead of 30,000). The annual effective rate of interest is 10%. a) Find the initial loan amount. (4 points) b) Find the Macaulay duration for this loan structure. (6 points) A 20-year mortgage is to be repaid with level annual end-of-year payments of 30,000 except that at both t = 10 and t = 20, the amount repaid is 150,000 (instead of 30,000). The annual effective rate of interest is 10%. a) Find the initial loan amount. (4 points) b) Find the Macaulay duration for this loan structure. (6 points)