Problem 3-13 Duration Calculate the durations and volatilities of securities A, B, and C. Their cash flows are shown below. The interest rate is 9%. (Do not round intermediate calculations. Round "Duration" to 4 decimal places and "Volatility" to 2 decimal places.) Period 1 120 Period 2 120 Volatility Period 3 200 280 Duration years years years 100 100 3 C 90 90 270