Please help me solve.

Williamson, Inc., has a debt-equity ratio of 2.53. The company's weighted average cost of capital is 10 percent, and its pretax cost of debt is 6 percent. The corporate tax rate is 23 percent. a. What is the company's cost of equity capital? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) b. What is the company's unlevered cost of equity capital? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) c. What would the weighted average cost of capital be if the company's debt-equity ratio were .65 and 1.65 ? (Do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 32.16.)