Perpetual Inventory Using FIFO Beginning inventory, purchases, and sales for Item Zeta9 are as follows: Oct. 1 Inventory 78 units @ $20 7 Sale 57 units 15 Purchase 74 units @ $24 24 Sale 27 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 13