What is the WACC for a firm with 40% debt, 20% preferred stock and 40% equity if the respective costs for these components are 8% after-tax, 13% after-tax, and 17% before-tax? The firm's tax rate is 35%.

What is the WACC for a firm with equal amounts of debt and equity financing, a 15% before-tax company cost of capital, a 35% tax rate, and a 12% coupon rate on its debt that is selling at par value?

Please include the steps as well please.