What is the weighted average cost of capital if a business has a cost of equity of $11\%,$ a yield on debt of $6\%,$ a tax rate of $30\%,100$ million market value of debt, and $250$ million market value of equity?$9\mathrm{.}06\%9\mathrm{.}57\%8\mathrm{.}5\%7\mathrm{.}6\%$