Williamson, Inc. has a debt-equity ration of 2.5. The firms weighted average cost of capital is 10% and its pre-tax cost of debt is 6%. Williamson faces a corporate tax rate of 35%.

1. What is Williamsons cost of equity capital?
2. What is Williamsons unlevered cost of equity capital?
3. What would Williamsons WACC be if the firms debt-equity ratio were 0.75? What is it were 1.5?

Please write the whole of process on excel,thanks.