Kose, Inc., has a target debt-equity ratio of 1.47. Its WACC is 8.7 percent, and the tax rate is 21 percent.

a. If the companys cost of equity is 16 percent, what is its pretax cost of debt? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)

b. If instead you know that the after-tax cost of debt is 6.1 percent, what is the cost of equity?

Please solve using excel and show your equation set up.