Step-by-step explanation:
The solution can be made in tabular form as given below for better comprehension. This easily calculates gross profit for each of the four costing methods.
Particulars FIFO LIFO Avg cost Spec. ID
Sales 50900 50900 50900 50900
Cost of goods sold 31800 32920 32248 32540
Gross Profit 19100 17980 18652 18360