A jewelry firm buys semiprecious stones to make bracelets and rings. It uses $80$ stones a day

in its process. The person who orders the stones replenishes the stock as soon as the amount on

hand drops to $700$ stones. The delivery time of orders is normal with an average of $6$ days and a

standard deviation of $1$ day. Calculate the risk of a stocking out of semiprecious stones before an

order arrives.

Hint: Find the service level from the ROP and then find the stockout risk.