Problem 7-15 Economic ordering quantity with safety stock [LO7-5] Diagnostic Supplies has expected sales of 158,700 units per year, carrying costs of $3 per unit, and an ordering cost of $8 per order: a. What is the economic ordering quantity? b-1. What is the average inventory? b-2. What is the total carrying cost? Assume an additional 40 units of inventory will be required as safety stock. c-1. What will the new average inventory be? c-2. What will the new total carrying cost be