Problem $14-9$ Calculating WACC $[$LO$3]$

Ninecent Corporation has a target capital structure of $65$ percent common stock, $10$ percent preferred stock, and $25$ percent debt. Its cost of equity is $9$ percent, the cost of preferred stock is $4$ percent, and the pretax cost of debt is $5$ percent. The relevant tax rate is $21$ percent.

a$.$ What is the company's WACC? $($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? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

$\backslash$table$[[$a$.$ WACC,$7\mathrm{.}88,\%$