Please help me with a,b,c. Help me understand and show your work. Thank you

Cheggs answer is incorrect

21. Cost of Capital Harris, Inc., has equity with a market value of $18.5 million and debt with a market value of $7.3 million. Treasury bills that mature in one year yield 4 percent per year and the expected return on the market portfolio is 11 percent. The beta of the company's equity is 1.15 . The firm pays no taxes. a. What is the company's debt-equity ratio? b. What is the firm's weighted average cost of capital? c. What is the cost of capital for an otherwise identical all-equity firm