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 300 units. Date Units Unit Cost Total Cost Beginning Inventory January 1 240 $ 75 $ 18,000 Purchase January 15 320 85 27,200 Purchase January 24 240 105 25,200 Required: Calculate the number and cost of goods available for sale. Calculate the number of units in ending inventory. Calculate the cost of ending inventory and cost of goods sold using the (a) FIFO, (b) LIFO, and (c) weighted average cost methods