a) The expected annual demand of one product is 20000 units. Ordering cost is 120 JD per order. Holding cost is 20% of a unit price. The company operates 280 days per year. The company received the following offer Quantity (units) 1-999 1000-1999 2000 and over Price (JD) 9 8.8 8.6 a) Determine the optimal order quantity and the minimum total cost b) Determine the maximum inventory level c) Determine the average inventory d) Determine the expected time between orders b) One firm currently orders 180 units per order of one product. They incur an annual holding cost of 12 JD per unit and have an ordering cost of 75 JD each time they place an order. If their annual demand is 1800 units, how much could they save annually by switching to their economic order quantity?