Please show the calculations:

a. Northwest Co. (NW) has currently outstanding bonds with a 10% coupon and 7% yield to maturity. NW could issue new bonds at par that would provide the same YTM. If NW's marginal tax rate is 21%, what is NW's after-tax cost of debt?

b. NW is also thinking about issuing preferred stock. If the price would be $100 per share with an annual

dividend of $7.50 per share, what is the company's cost of preferred stock?

c. You have been asked to estimate the required return on common stock for NW. If beta = 0.9, the yield on a 10-year T-bond is 5% and the market risk premium is 7%, what is the estimated cost of common equity?