Answer:
The answer are:
Explanation:
Since earnings from municipal bonds are exempt from income taxes, their after tax rate of return is 5% (doesn't vary).
On the other hands earnings from corporate bonds are taxed by 15%. To calculate the after tax rate of return we multiply:
nominal rate of return x (1 - tax rate) = 6.4% x (1 - 15%) = 6.4% x 0.85 = 5.44%