The units of an item available for sale during the year were as follows:

Jan. 1

Inventory

12 units at $25

$ 300

Apr. 20

Purchase

28 units at $30

840

Nov. 30

Purchase

40 units at $36

1,440

 

Available for sale

80 units

$2,580

There are 20 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.