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 310 units. Date Units Unit Cost Total Cost Beginning Inventory January 1 240 $ 80 $ 19,200 Purchase January 15 360 90 32,400 Purchase January 24 200 110 22,000 Calculate the cost of ending inventory and cost of goods sold using the (a) FIFO, (b) LIFO, and (c) weighted average cost methods.