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 Kikis records show the following for the month of January. The company sold 280 units between January 16 and 23. Date Units Unit Cost Total Cost Beginning Inventory January 1 220 $ 90 $ 19,800 Purchase January 15 480 100 48,000 Purchase January 24 200 120 24,000