Perpetual Inventory Using FIFO Beginning inventory, purchases, and sales for Item Zeta9 are as follows: Oct. 1 Inventory 35 units @ $25 7 Sale 23 units 15 Purchase 21 units @ $30 24 Sale 18 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