Additional Algo $11-4$ On$-$Order Quantity

A restaurant orders supplies every $3$ days. The lead time for deliveries is $4$ days. Demand for butter averages $12$ pounds per day with a

standard deviation of $1\mathrm{.}5$ pounds. The holding cost for butter is $$0\mathrm{.}75$ per pound per day. The restaurant wants to achieve an in$-$stock

probability rate of $90\%$ for butter.

On average, how many pounds of butter will.the restaurant have on order?