The following lots of a particular commodity were available for sale during the year: Beginning inventory First purchase Second purchase Third purchase 10 units at $30 25 units at $32 30 units at $34 10 units at $35 2. The fim uses the periodic sy stem and there are 20 units of the commodity on hand at the end of the year. What is the amount of inventory at the end of the year according to the LIFO mcthod? a. $659 $620 c $655 d. $690 The firm uses the periodic system and there are 20 units of the commodity on hand at the end of the year. What is the amount of inventory at the end of the year according to the average cost method? 3. a. $659 b. $620 C. $655 d. $690