erpetual Inventory Using LIFO Beginning inventory, purchases, and sales for Item ER27 are as follows: October 1 Inventory 86 units @ $35 5 Sale 69 units 11 Purchase 95 units @ $39 21 Sale 80 units Assuming a perpetual inventory system and using the last-in, first-out (LIFO) method, determine (a) the cost of merchandise sold on October 21 and (b) the inventory on October 31. a. Cost of merchandise sold on October 21 $ b. Inventory on October 31 $