If the cost price of 50 articles is equal to the selling price of 40 articles, then the gain or loss percent is?

A. 20% loss
B. 20% profit
C. 10% profit
D. 25% loss
E. None of these
Explanation:
Given that, cost price of 50 article is equal to selling price of 40 articles.
Let cost price of one article = Rs. 1
Selling price of 40 articles = Rs. 50
But Cost price of 40 articles = Rs. 40
Therefore, the trader made profit.Percentage of profit = 10/40 * 100 = 25%