The managing partner at Sarah's Accounting Service typically hires one part$-$time intern to complete her clients' basic tax returns.

Sarah expects her intern to complete $300$ of these basic returns, estimating each one to take $30$ minutes of the intern's time. Sarah

pays her intern $$\frac{20}{?}$ hour and incurs additional variable overhead costs of $$\frac{19}{?}$ hour associated with the resources that are needed

behind the scenes for these jobs. What cost of services should Sarah budget for all basic tax returns this season, and how much should

she charge each client if she wants to earn $60\%$ gross margin on each of these returns? $($Round sales price per unit to $2$ decimal places, e$.$g$.$

$15\mathrm{.}25.)$