Beginning inventory, purchases, and sales for an inventory item are as follows: Sept. 1 Beginning Inventory 28 units $12 S Sale 16 units 17 Purchase 31 units $15 30 Sale 30 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