Final answer:
To determine the federal tax rate at which you would be indifferent between the two bonds, subtract the federal tax rate from the pre-tax yield of the corporate bond and set it equal to the pre-tax yield of the municipal bond.
Step-by-step explanation:
To determine the federal tax rate at which you would be indifferent between the two bonds, we need to calculate the after-tax yields of each bond. Since the state tax rate is zero, the after-tax yield of the municipal bond is simply its pre-tax yield of 6.50%. For the corporate bond, we need to subtract the federal tax rate from the pre-tax yield to get the after-tax yield. Let's call the federal tax rate 'r'. The after-tax yield of the corporate bond is then 10.70% - r.
Since you are indifferent between the two bonds, their after-tax yields must be equal. Therefore, we can set up the following equation:
6.50% = 10.70% - r
Solving for 'r', we find that the federal tax rate at which you would be indifferent between the two bonds is 4.20%.