Royal Petroleum Co. can buy a piece of equipment that is anticipated to provide a 9 percent return and can be financed at 6 percent with debt. Later in the year the firm turns down an opportunity to buy a new machine that would yield a 16 percent return but would cost 18 percent to finance through common equity. Assume debt and common equity each represent 50 percent of the firm’s capital structure.

How do you Compute the weighted average cost of capital.

Re = cost of equity 0.18
Rd = cost of debt /rate of debt 0.06
E = the market value of the firm's equity 50000
D = the market value of the firm's debt 50000
V = E + D 100000
Tc = the corporate tax rate
WACC = (E/V)*Re + (D/V)*Rd*(1-Tc) 12.000%