Please show work

You were hired as a consultant to Sharp Rocks Company, whose target capital structure is 40% debt, 15% preferred, and 45% common equity. The after-tax cost of debt is 6.00%, the cost of preferred is 7.50%, the cost of common stock is 12.75%, and the marginal tax rate is 40%. The firm will not be issuing any new stock. What is its WACC