Problem $2(15$ points$).$ Drug Inc. sells a high runner product that is ordered every $20$ days when a sales person visits from one of the pharmaceutical companies. This product has an average daily demand of $1,500$ units. The standard deviation of daily demand was calculated from evaluating data over the past three months and was found to be $550$ units. Once an order is started, it takes seven days to arrive. The company would like to satisfy $95$ percent of their demand. The sales person just arrived, and there are currently $10,000$ units in warehouse.

a$.(15$ points$).$ How many units should be ordered during that Time Period? Formula $=$ Reorder point $($time period$)-$ On hand inventory