Dusit is financed $36\%$ by debt yielding $8\mathrm{.}6\%.$ Investors require a return of $15\mathrm{.}6\%$ on Dusit's equity.

a$.$ What is the company's weighted$-$average cost of capital if the corporate tax rate is $21\%?$

b$.$ What would be the company's cost of capital if it were exempted from corporate tax?

Note: For all the requirements, do not round intermediate calculations. Enter your answers as a percent rounded to $2$ decimal places.

a$.$ Weighted$-$average cost of capital

b$.$ Weighted$-$average cost of capital

$\frac{\%}{\%}$