71. What is the WACC for a firm with 40% debt, 20% preferred stock, and 40% equity if their respective costs are 9.23% before tax, 12%, and 18%? The firm's tax rate is 21%. 72. What is a firm's weighted-average cost of capital for a firm that is financed 45% by debt? The debt has a 10% required return and the equity has a 17% required return. The tax rate is 21%. 73. What is the WACC for a firm with 20% debt, 20% preferred stock, and 60% equity if their respective costs are 6% after tax, 12%, and 18%? The firm's tax rate is 21%. 74. What is the WACC for a firm with 60% debt, no preferred stock, and 40% equity if their respective costs are 6% after tax, 12%, and 18%? The firm's tax rate is 21%. 75. What is the WACC for a firm with 30% debt, 20% preferred stock, and 50% equity if their respective costs are 6% after tax, 12%, and 18%? The firm's tax rate is 21%.