If the tax rate is 25 percent, compute the before-tax real interest rate and the after-tax real interest rate in each of the following cases. a) The nominal interest rate is 10 percent, and the inflation rate is 5 percent (5 marks) b) The nominal interest rate is 6 percent, and the inflation rate is 2 percent (5 marks) c) The nominal interest rate is 4 percent, and the inflation rate is 1 percent (5 marks)