Answer: 12.29%
Explanation:
Municipal bonds are tax exempt and so are attractive for this reason. If John is to be indifferent between the two, the corporate bond would have to offer a return that when adjusted for tax, will give the same return as the municipal bond.
Assume that return is x;
x * ( 1 - 17%) = 10.2%
0.83x = 10.2%
x = 10.2%/0.83
x = 12.29%