Monster Mining Corporation has $1$ million shares of common stock outstanding, $50,000$ shares of $7$ percent preferred stock outstanding and $10,000$ eight percent $($semiannual$)$ coupon bonds outstanding, par value $$1,000$ each. The common stock currently sells for $$40$ per share and has a beta of $1\mathrm{.}3,$ the preferred stock currently sells for $$75$ per share, and the bonds have $22$ years to maturity and sell for $110$ percent of par. The market risk premium is $8\mathrm{.}6$ percent, T$-$bills are yielding $4\mathrm{.}5$ percent, and the firm's tax rate is $34$ percent.

What is the after$-$tax cost of debt?