Perpetual inventory using FIFO Beginning inventory, purchases, and sales for Item Zeta9 are as follows: Date Line Item Description Value Oct. 1 Inventory 36 units @ $21 Oct. 7 Sale 24 units Oct. 15 Purchase 36 units @ $23 Oct. 24 Sale 20 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