Answer:
The tax rate is approximately(rounded to a whole) 29%
Explanation:
The federal tax that would make an investor indifferent between the 5-year corporate bond and the 5-year municipal bond can be derived by equating the return on the former to the taxable return of the latter as below:
5%=7%*(1-t)
where the t is the unknown tax rate
Note that the return on 5-year corporate bond is taxable while the return on the municipal bond is tax-free
5%=7%*(1-t)
5%/7%=1-t
0.7143 =1-t
t=1-0.7143
t=29%
