aircard corporation tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method at the end of each period as if it uses a perpetual inventory system. the following are the transactions for the month of july. units unit cost july 1 beginning inventory 2,000 $ 40 july 5 sold 1,000 july 13 purchased 6,000 44 july 17 sold 3,000 july 25 purchased 8,000 50 july 27 sold 5,000 required: calculate the cost of ending inventory and cost of goods sold assuming a perpetual inventory system is used in combination with (a) fifo and (b) lifo.