Problem 12.17 You are given 8 = 9:5, for t > 0. A payment of 400 at the end of 3 years and 800 at the end of 15 years has the same present value as a payment of 300 at the end of 8 years and X at the end of 24 years. Calculate X. Problem 12.17 You are given 8 = 9:5, for t > 0. A payment of 400 at the end of 3 years and 800 at the end of 15 years has the same present value as a payment of 300 at the end of 8 years and X at the end of 24 years. Calculate X