Carla Vista Co. has a capital structure, based on current market values, that consists of 25 percent debt, 15 percent preferred stock. and 60 percent common stock, If the returns required by investors are 9 percent, 10 percent, and 15 percent for the debt, preferred stock, and common stock, respectively, what is Carla Vista's after-tax WACC? Assume that the firm's marginal tax rate is 28 percent. (Do not round intermediote calculations. Round answer to 1 decimal ploce, es. 15.2\%.) After tax WACC