Situational Software Co$.($SSC$)$ is trying to establish its optimal capital structure. Its current capital structure consists of $40\%$ and $60\%$equity; however, the CEO believes that the firm should use more debt. The risk$-$free rate, rF$,$ is $3\%$; the market risk premium, RPM$,$ is $5\%$; and the firm's tax rate is $25\%.$ Currently, SSC$\text{'}$s cost of equity is $15\%,$ which is determined by the CAPM.

What would be SSC$\text{'}$s estimated cost of equity if it changed its capital structure to $50\%$ debt and $50\%$ equity? Round your answer to two decimal places. Do not round intermediate steps.