answer for both part a and b please

3. Curtis invests $300,000 in a Torrance School District bonds 5% interest. Alternatively, Curtis could have invested the $300,000 bonds recently issued by Boeing that 9% interest with similar risk as the Torrance School District bonds. Assume that Curtis's pays marginal tax rate is 32%. a) If Curtis invested in the Torrance School District bonds what would be his after-tax rate of return from this investment? b) If Curtis invested in the Boeing bonds what would be his after-tax rate of return from this investment