The risk-free rate is 5%, the market risk premium (=E(RM) - RF) is 10%. Assume CAPM holds. A firm has a debt-to-equity ratio of 0.5. The firm's before-tax cost of debt is 10%. The firm's tax rate is 30%. If it had no debt, its cost of equity would be 15%.

a) What is the beta of the firm's debt?

b) what is the beta of the firm's equity in the firm had no debt?

c) What is the beta of the firm's equity when the debt to equity is .05?

d) What is the cost of the firm's equity when the debt-to-equity ratio is 0.5?