On selling three articles at the cost of four article, there will be profit of ______?

Answer 1

Let x be the price of 1 article.

Normally 3 articles cost 3x and 4 articles cost 4x.

Selling 3 for 4x is a price difference of 4x-3x)=x <--- profit

x/3x = 1/3 = 33 and 1/3 % profit