Ben Electronics has a capital structure consisting of 41 percent common stock and 59 percent debt. A debt issue of $1,000 par value, 6.5 percent bonds that mature in 15 years and pay annual interest will sell for $975. Common stock of the firm is currently selling for $33 per share and the firm expects to pay a $6.48 dividend next year. Dividends have grown at the rate of 3.8 percent per year and are expected to continue to do so for the foreseeable future. The firm's tax rate is 35 percent.

Question: Ben's cost of capital is ?

write the equation in detail please, thank you!