Thirty-five percent of R.B.H. Bicycle Corp.s total capital is debt, 45% is from the issuance of stock,

Question:

Thirty-five percent of R.B.H. Bicycle Corp.’s total capital is debt, 45% is from the issuance of stock, and 20% is equity from retained earnings. The company has determined that the cost of its debt capital is 8% and the cost of its equity capital is 18% from stock and 15% from retained earnings.
Compute R.B.H’s average cost of capital.