A particular raw material is available to a company at three different prices, depending on the size of the order:
Less than 100 pounds - $20 per pound
100 pounds to 999 pounds - $19 per pound
More than 1,000 pounds - $18 per pound
The cost to place an order is $40. Annual demand is 3,000 units. Holding (or carrying) cost is 25 percent of the material cost. What is the economic order quantity to buy each time?