Answer:
(a) 13
(b) LIFO: $19.60; FIFO: $37.50; Avg: $28.26
Explanation:
(a) The starting inventory was 12 sets. Added to that were 4, 6, 6, 10, to make a total of 38 paint sets. 25 were sold, so 13 remained at the end of the year.
(b)
LIFO
Sets purchased at the end of the year are sold first (last-in, first-out). So the sets remaining in inventory are the ones purchased at the beginning of the year. Those 13 sets cost [email protected] [email protected] = $19.60.
FIFO
Sets purchased first are sold first, so the sets remaining in inventory are the ones purchased last. Those 13 sets cost [email protected] [email protected] = $37.50.
Avg
The total cost of all inventory purchases was ...
... [email protected] [email protected] [email protected] [email protected] [email protected]
... = 18.00 +6.40 +13.20 +15.00 +30.00 = $82.60
Then the value of the remaining 13 of the 38 items bought is ...
... (13/38)·$82.60 = $28.26.
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I find it convenient to let a spreadsheet do the arithmetic.