The following information was available from the inventory of Key Company for January Units Unit Cost Balance at Jan 1 3,000 $9.77 Purchases: Jan 6 2,000 10.30 Jan 26 2,700 10.71 Sales: Jan 7 (2,500) Jan 31 (4,200) Required: a. Assuming that the Perpetual Inventory system is used, what should be the COGS and ending inventory at January 31" using the moving average inventory method? b. Assuming that the Periodic Inventory system is used, what should be the COGS and ending inventory at January 31s using the weighted average method