Inventory Costing Methods Tyler Company has the following information related to purchases and sales of one of its inventory items. Date Description Units Purchased at Cost Units Sold at Retail Sept. 1 Beginning inventory 400 units @ $10 Sept. 10 Purchase 600 units @ $11 Sept. 20 Sales 700 units @ $19 Sept. 25 Purchase 800 units at $13 Assume the company uses a perpetual inventory system