Perpetual Inventory Using FIFO Beginning inventory, purchases, and sales for Item ER27 are as follows: July 1 Inventory 75 units @ $25 9 Sale 54 units 13 Purchase 85 units @ $27 28 Sale 30 units Assuming a perpetual Inventory system and using the first-in, first-out (FIFO) method, determine (a) the cost of merchandise sold on July 28 and (b) the inventory on July 31. a. Cost of merchandise sold on July 28 b. Inventory on July 31