Beginning inventory, purchases, and sales for an inventory item are as follows: Beginning inventory 28 units 529 Dec 1 Sale 4 18 unit Purchase 15 unit $34 15 Sale 20 units 31 Assuming a perpetual inventory system and the last-in, first-out (LIFO) method, determine (a) the cost of the goods sold for the December 31 sale and (b) the inventory on December 31