Perpetual Inventory Using LIFO Beginning inventory, purchases, and sales for Item PK95 are as follows: July 1 Inventory 82 units @ $33 5 Sale 66 units 11 Purchase 91 units @ $36 21 Sale 76 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