A man purchased some article at the rate of 25 for ₹ 1. How many articles should he sell for ₹1 to gain 25%?

20 15 18 22

20

CP = Rs. \(\frac{1}{25}\) SP = \(\frac{1}{25}\) × \(\frac{125}{100}\) =  \(\frac{1}{20}\)     =  20 for Rs. 1