Question 1019635
Let x = cost of each article.
We use the formula Profit = Revenue - Cost.
Profit = 48, as mentioned.
Revenue = 400.
If there were 16 articles, the total cost would be 16x.

Thus, after substitution, we get

48 = 400 - 16x
==>16x = 400 - 48 = 352

==>x = 352/16
x = 22

Therefore each article cost him $22.