Suppose the tax rate on interest income is 25 percent, the real interest rate is 4 percent, and the inflation rate is 4 percent. The real after-tax...

Suppose the tax rate on interest income is 25 percent, the real interest rate is 4

percent, and the inflation rate is 4 percent. The real after-tax interest rate is

The correct answer is: 2.0 percent

Why is it 2% and not 4%? How is this calculated?