Question $1$

Demand for a coffee cup is normally distributed with a mean of $20$ units per week and a

standard deviation in weekly demand of $5$ units. The lead time is $2$ weeks, and the business

operates $50$ weeks per year. The continuous review system called for an EOQ of $100$ units

and a cycle$-$service level of $90$ percent $($for $90\%$ service level, assume the value of $z=1\mathrm{.}28).$

What is the time between reviews under periodic review system $(P$ system$)?$

$127$ units

$147$ units

$157$ units

$137$ units

$117$ units