Perpetual Inventory Using FIFO Beginning inventory, purchases, and sales for Item Zeta9 are as follows: Oct. 1 Inventory 36 units @ $21 Sale 27 units 15 Purchase 32 units $24 24 Sale 17 units Assuming a perpetual inventory system and using the first-in, first-out (FIFO) method, determine (a) the cost of goods sold on October 24 and (b) the inventory on October 31. a. Cost of goods sold on October 24 b. Inventory on October 31 357 X 120 X