A bank has two, 3-year commercial loans with a present value of $70 million. The first is a $30 million loan that requires a single payment of $37.8 million in 3 years, with no other payments till then. The second is for $40 million. It requires an annual interest payment of $3.6 million. The principal of $40 million is due in 3 years. (a) (10 points) What is the duration of the banks commercial loan portfolio? (b) (10 points) What will happen to the value of its portfolio if the general level of interest rates increased from 8% to 8.5%?