A firm$$s bondholders are earning a $7\mathrm{.}5\%$ return and the firm$$s stockholders are earning a $15\%$ return. The firm$$s financing is $35\%$ debt and $65\%$ equity. The firm$$s average tax rate is $27\%.$

What is the firm$$s cost of equity?

Group of answer choices

$7\mathrm{.}5\%$

$15\%$

$35\%$

$65\%$

$13\%$

$10\%$