A dealer allows 25% discount on the marked price of an article and gains 20%. If the cost price of the article increases by 20%, how much discount percentage should he allow on the marked price so as to earn the same percentage of profit as before?

10%

Let MP = 100

SP of the article = 100 × \(\frac{3}{4}\) = Rs. 75 

According to the question

Profit = 20%

120% of C.P = 75

 CP of the article = 75 × \(\frac{5}{6}\)  = 62.5

Again According to the question

New CP = 62.5 × \(\frac{6}{5}\) = Rs. 75

 New SP = 75 × \(\frac{6}{5}\) = Rs. 90

Discount percentage = \(\frac{100 - 90}{100}\)  × 100 =  10%