Nuttenhall Corporation has a target capital structure of $65$ percent common stock, $10$ percent preferred stock, and $25$ percent debt. Its cost of equity is $12$ percent, the cost of preferred stock is $6$ percent, and the pretax cost of debt is $7$ percent. The relevant tax rate is $24$ percent.

a$.$ What is the company's WACC?

Note: Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

b$.$ What is the aftertax cost of debt?

Note: Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

a$.$ WACC

b$.$ Cost of debt

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