High Tech, Inc. is a virtual store that stocks a variety of cell phones in their warehouse. Customer orders are placed, picked and packaged, and then shipped to the customer. A fixed$-$order quantity inventory$-$control system $($FQS$)$ helps monitor and control these SKUs. The following information is for one of the cell phones that they stock, sell, and ship:

$\backslash$table$[[$Average demand,$12\mathrm{.}5$ cell phones per week$],[$Lead time,$3$ weeks$],[$Order cost$,$$$\frac{20}{?}$ order$],[$Unit cost$,$$$8\mathrm{.}00$