E7-7 Calculating Cost of Ending Inventory and Cost of Goods Sold under Periodic FIFO, LIFO, and Weighted Average Cost Oahu Kiki tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method at the end of each month, as if it uses a periodic inventory system. Assume Oahu Kiki's records show the following for the month of January. Sales totaled 240 units. Date Units Unit Cost Total Cost Beginning Inventory January 1 120 $ 80 $ 9,600 Purchase January 15 380 90 34,200 Purchase January 24 200 110 22,000 Required: 1. Calculate the number and cost of goods available for sale. 2. Calculate the number of units in ending inventory. 3. Calculate the cost of ending inventory and cost of goods sold using the (a) FIFO, (b) LIFO, and (c) weighted average cost methods.