Beginning inventory, purchases, and sales for an inventory item are as follows: Sep. 1 Beginning Inventory 31 units $21 5 Sale 18 units 17 Purchase 33 units @ $23 30 Sale 33 units Assuming a perpetual inventory system and the first-in, first-out method: a. Determine the cost of the goods sold for the September 30 sale. b. Determine the inventory on September 30. $