Perpetual Inventory Using FIFO Beginning inventory, purchases, and sales for Item Zeta 9 are as follows: Oct. 1 Inventory 55 units $18 39 units 7 Sale 15 Purchase 40 units $21 24 Sale 21 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 31 940