Question $18$

$0\mathrm{.}5pts$

Daily demand of Dulcolax tablets in a drug store follows a normal distribution with an average demand of $50$ strips of tablets and standard deviation of demand equal to $20$ strips. It takes $4$ days to supply the order placed by the drug store $($i$.$e$.,$ lead time$).$ The store wants to maintain $95\%$ customer service level $($for $95\%$ service level, assume the value of $z=1\mathrm{.}64)$ and monitors its inventory continuously. What is the approximate safety stock?

$46$

$56$

$86$

$76$

$66$