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 @ $20 10 Purchase 600 units @ $21 20 Sales 620 units @ $36 25 Purchase 800 units at $23 Assume Tyler uses a perpetual inventory system. Required: Calculate ending inventory and cost of goods sold using the FIFO, LIFO, and average cost methods.