Idaho Engineering Inc. has a target capital structure of 39% debt, 10% preferred stock and 51% common stock. The interest rate on new debt is 4.2%, the yield on preferred stock is 8% and the cost of retained earnings is 10%. The firm will not be issuing any new stock, and the tax rate is 35%.

What is the company's pre-tax weighted average cost of capital?

What is the company's after-tax weighted average cost of capital?