Date Description Units Purchased at Cost Units Sold at Retail March 1 Beginning Inventory 300 units at $12 March 2 Purchase 400 units at $24 March 6 Sale 600 at $50 March 13 Purchase 500 units at $28 March 20 Sale 550 at $50 Assuming a perpetual inventory system: a) Calculate the cost of merchandise sold for March using the last-in, first-out (LIFO) method. (show workings). b) Calculate the cost of ending inventory on March 31 using the last-in, first-out (LIFO) method. (show workings)