Perpetual Inventory Using LIFO Beginning inventory, purchases, and sales for Item ER27 are as follows: July 1 Inventory 94 units $20 5 Sale 75 units 11 Purchase 104 units $23 21 Sale 87 units Assuming a perpetual inventory system and using the last in, fest 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