Based on available intormation, lead time demand for PC thumb drives averages $50$ units $($normally distributed$),$ with a slandard deviation of $5$ dives. Management wants an $85\%$ service level Refer to the standard normai table for $z-$values.

a$)$ What value of $Z$ should be applied?

b$)$ How many drives should be carried as safety slock? $$ units $($round your respanse to the nearest whole number$).$

c$)$ What is the appropriate reorder point? $$ units $($round your response to the nearest wholo number$).$