really need hw help

Calculate the after-tax return of a 11.35 percent, 20-year, A-rated corporate bond for an investor in the 15 percent marginal tax bracket. Compare this yield to a 7.52 percent, 20-year, A-rated, tax-exempt municipal bond, and explain which alternative is better. Repeat the calculations and comparison for an investor in the 35 percent marginal tax bracket. The after-tax return of a 11.35 percent, 20-year, A-rated corporate bond for an investor in the 15 percent marginal tax bracket is % (Round to two decimal places.)