As we are only interested in the cost, we will ignore the sale price, only purchase prices.
The movements are:
1) We have an initial inventory of 21 units at $42 each.
2) Sale of 14 units, so the inventory is reduced by 14 units.
3) Purchase of 18 units at $44, so the inventory is increased by 18 units.
4) Sale of 6 units, so the inventory is reduced by 6 units.
5) Purchase of 24 units at $47.
6) Sale of 21 units.
The ending inventory after this movements is 22 units.
We can calculate the cost in a FIFO system by substracting the sold units from the group that was first purchased.
In this case, we can calculate the cost as:
1) We have 21 units at $42.
2) The first sale is of 14 units, so they have a cost of 14 units of $42 each. The stock is now: 21-14 = 7 units at $42.
3) We increase the inventory by 18 units at $44, so the stock is now: 7 units at $42 and 18 untis at $44.
4) The sale of 6 units can still be satisfied with the original inventory of 7 units at $42, so the cost is 6 units at $42 each. Now the stock is: 1 unit at $42 and 18 units at $44.
5) Purchase of 24 units at $47. So the stock is now: 1 unit at $42, 18 units at $44 and 24 units at $47.
6) Sale of 21 units. We then will take the cost of 1 unit at $42 (the last from the original inventory), 18 units at $44 and the remaining 2 units at $47.
We now can add all the cost of each unit sold as:
The total cost according to FIFO is $1768.
Now, if we use LIFO (last in, first out) we will take the inventory from the last purchase first.
1) We have 21 units at $42.
2) The first sale is of 14 units, so they have a cost of 14 units of $42 each. The stock is now: 21-14 = 7 units at $42.
3) We increase the inventory by 18 units at $44, so the stock is now: 7 units at $42 and 18 untis at $44.
4) The sale of 6 units will be substracted from the inventory purchased at $44, so we will have a cost of 6 units at $44. The stock will now be: 7 units at $42 and 12 units at $44.
5) Purchase of 24 units at $47. So the stock is now: 7 units at $42, 12 units at $44 and 24 units at $47.
6) Sale of 21 units. We then will take the cost from the units in the last purchase: 21 units at $47.
Now we can calculate the total cost as:
The total cost according to LIFO is $1839.
Answer:
a) The total cost according to FIFO is $1768.
b) The total cost according to LIFO is $1839.