Beginning Inventory, purchases, and sales for an inventory item are as follows: Sept. 1 Beginning Inventory 21 units $20 5 Sale 12 units 17 Purchase 22 units $21 30 Sale 23 units Assuming a perpetual Inventory system and the first-in, first-out method, determine (a) the cost of the merchandise sold for the September 30 sale and (b) the inventory on September 30. a. Cost of merchandise sold b. Inventory, September 30