Demand for doughnut holes on Saturdays at Don$$s Doughnut Shoppe is shown in the following table.

Demand

$($dozens$)$ Relative

Frequency Demand

$($dozens$)$ Relative

Frequency

$19\mathrm{.}0425\mathrm{.}10$

$20\mathrm{.}0526\mathrm{.}14$

$21\mathrm{.}1327\mathrm{.}10$

$22\mathrm{.}0328\mathrm{.}05$

$23\mathrm{.}1129\mathrm{.}07$

$24\mathrm{.}18$

Click here for the Excel Data File

a$-1.$ Determine the optimal number of doughnut holes, in dozens, to stock if labor, materials, and overhead are estimated to be $$6\mathrm{.}40$ per dozen, doughnut holes are sold for $$8\mathrm{.}00$ per dozen, and leftover doughnut holes at the end of each day are sold the next day at half price. $($Round your answer to the nearest whole number.$)$

a$-2.$ What is the resulting service level? $($Round your answer to $2$ decimal places.$)$