please help with excel step-by-step (detailed) much appreciated **IMPORTANT** PLEASE MAKE SURE TO USE EXCEL WITH FORMULAS

A firm is planning to change its capital structure. Its current capital structure consists of 65% common equity, 25% debt, and 10% preferred stock. The pre-tax cost of debt is 4%, cost of preferred stock is 6% and cost of common equity is 12%. What is the change in its WACC (indicate an increase or a decrease in WACC) if this firms plan to adopt a new capital structure with 60% common equity, 15% debt, and 25% preferred stock if the costs for these components are 3% after-tax cost of debt, 8% cost of preferred stock, and 15% cost of common equity? The firm's tax rate stays at 40%.

PLEASE HELP WITH EXCEL STEP-BY-STEP (IN FULL detail) much appreciated **IMPORTANT** I WANT TO LEARN