Beginning inventory, purchases, and sales for an inventory item are as follows: Beginning inventory 20 unit $24 Dec 1 Sale 15 units 4 Purchase 24 units 826 15 Sale 12 units 31 Assuming a perpetual inventory system and the first-in, first-out (FIFO) method, determine (a) the cost of the goods sold for the December 31 sale and (b) the inventory on December 31.