The cost price of 20 articles is the same as the selling price of x articles. If the profit is 25%, then the value of x is:

Let C.P. of each article be Re. 1 C.P. of x articles = Rs. x. 

S.P. of x articles = Rs. 20. 

Profit = Rs. (20 - x). 

$\frac{20-x}{x}*100=25$ 

=> 2000 - 100x = 25x 

=> 125x=2000 

=> x=16