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 Kikis records show the following for the month of January. Sales totaled 260 units. Date Units Unit Cost Total Cost Beginning Inventory January 1; 220 $ 80 $ 17,600 Purchase January 15; 480 90 43,200 Purchase January 24; 200 110 22,000 Required: Calculate the cost of ending inventory and cost of goods sold using the (a) FIFO, (b) LIFO, and (c) weighted average cost methods.