Perpetual Inventory Using LIFO Beginning inventory, purchases, and sales for Item ER27 are as follows: July 1 Inventory 86 units $33 5 Sale 69 units 11 Purchase 95 units $35 21 Sale 80 units Assuming a perpetual inventory system and using the last-in, first-out (LIFO) method, determine (a) the cost of merchandise sold on July 21 and (b) the inventory on July 31. a. Cost of merchandise sold on July 21 b. Inventory on July 31