Perpetual Inventory Using FIFO Beginning inventory, purchases, and sales for Item Copper are as follows: Mar. 1 Inventory 450 units at $7 9 Sale 390 units 13 Purchase 25 Sale 410 units at $8 340 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. a. Cost of merchandise sold on March 25 b. Inventory on March 31