May 1 - These records were kept for an inventory item in May. 100 units in opening inventory at $10 each May 5 - 50 units purchased at $10 each May 12 - 60 units sold May 20 - 20 units purchased at $8 each May 29 - 80 units sold Calculate the value of the closing inventory at May 31st (a) Using FIFO (b) Using LIFO (c) Using Average cost method