Perpetual Inventory Using LIFO Beginning inventory, purchases, and sales for Item CZ83 are as follows: October 1 Inventory 96 units @ $17 5 Sale 77 units 11 Purchase 107 units @ $19 21 Sale 90 units Assuming a perpetual inventory system and using the last-in, first-out (LIFO) method, determine (a) the cost of merchandise sold on October 21 and (b) the inventory on October 31. a. Cost of merchandise sold on October 21 $ b. Inventory on October 31 $