$15.$ How many units should be ordered given the following information:

Average demand $=$ d$-$bar $=1,200$ units per week

Review period $=$ T $=2$ weeks

Lead time $=$ L $=1$ week

$90\%$ probability of not stocking out $->$ Prob$(2<=0\mathrm{.}90)=1\mathrm{.}28$

Standard deviation of demand $=00=11$ units per week

Current inventory level $=1=1,124$ units