The daily sales of a peanut butter at Power's Grocery are normally distributed, with a mean of 12 jars and a standard deviation of 4. The manager checks the inventories on shelves and places an order every three days. Delivery lead time is two days and they carry 21 jars for safety stock. If there are 4 jars on the shelf when an order is placed, how much should the store order?
A) 77
B) 81
C) 32
D) 36

Question

Quizplus · Accepted Answer

The store sells 12 jars per day on average, so in three days, it sells 36 jars (12 jars/day * 3 days). If there are 4 jars on the shelf when an order is placed, the store needs to order enough to cover the sales for the next three days (36 jars), replenish the 4 jars already on the shelf, and maintain the 21 jars for safety stock. Therefore, the store should order 36 (for sales) + 21 (safety stock) + (36 - 4) (to replenish the shelf to the level it would be after three days' sales) = 36 + 21 + 32 = 77 jars.

The Daily Sales of a Peanut Butter at Power's Grocery