PE 7-4A Periodic inventory using FIFO, LIFO, average cost methods. Page 340 The units of an item available for sale during the year were as follows: Jan 1 Inventory 12 units at $45 $540 July 7 Purchase 18 units at $50 900 Nov 23 Purchase 15 units at $54 810 Available for sale 45 units $ 2250 There are 11 units of the item in the physical inventory at December 31. The periodic inventory system is used Determine the inventory cost using a) the first-in, first-out (FIFO) method; b) the last-in, first-out (LIFO) method; and c) the average cost method