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 250 units.

	Date	Units	Unit Cost	Total Cost
Beginning Inventory	January 1	100	$ 80	$ 8,000
Purchase	January 15	450	90	40,500
Purchase	January 24	200	110	22,000

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.