PE 7-2A Perpetual inventory using FIFO OBJ. 3 Beginning inventory, purchases, and sales for Item Copper are as follows: Mar. Inventory 450 units at $7 9 Sale 390 units 13 Purchase 410 units at $8 25 Sale 340 units Assuming a perpetual inventory system and using the first-in, first-out (FIFO) method, determine (a) the cost of merchandise sold on March 25 and (b) the inventory on March 31