Oahu Kiki tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method perpetually at the time of each sale, as if it uses perpetual inventory system. Assume Oahu Kiki's records show the following for the month of January. The company sold 280 units between January 16 and 23. Required: Calculate the cost of ending inventory and the cost of goods sold using the FIFO and LIFO methods