A firm has a target capital structure that consists of 45% of retained earnings and the rest in debt. The firm's cost of retained earnings is10.9%. The firm's cost of new debt is similar to the yield to maturity of its existing bonds, which is 4.4%. The firm's tax rate is 30%. Given this information, and given that the firm has no preferred stock, what is the WACC?

This is the way he gave us the formula.

WACC = Wd rd(1-T) + Wp rp + Ws rs + We re