Beginning inventory, purchases, and sales for an inventory item are as follows: Sep. 1 Beginning Inventory 35 units $17 5 Sale 20 units 17 Purchase 37 units $19 30 Sale 36 units Assuming a perpetual inventory system and the first-in, first-out method, determine (a) the cost of the goods sold for the September 30 sale and (b) the inventory on September 30. a. Cost of goods sold b. Inventory, September 30