A shopkeeper sold an article at profit of 10%. Had he bought it at 10% less and sold it for Rs. 3 more, then he would have earned a profit of 25%. Find the cost price of the article?

Let the cost price at = Rs. x So selling price at 10% profit = (x×110)/100 = 11x/10 According to question, New cost price 10% less = (x×90)/100 = 9x/10 New selling price = 11x/10 + 3 Profit = 25% So. 9x/10 × 125/100 = 11x/10 + 3 45x/40 - 11x/10 = 3 (45x-44x)/40 = 3 x = Rs. 120  ∴  Cost price of the article = Rs. 120 Alternate Method: Let cost price be Rs. 100  Selling price = Rs. 110 According to question,  New cost price = Rs. 90 ∴ New selling price = 90 × 125/100 = Rs. 112.5 on 25% profit, Difference in selling price 112.5 - 110 = 2.5 So. if cost price 100 so Difference is Rs. 2.5 but the actual difference is Rs. 3  So, cost price = 3/2.5 × 100 = Rs. 120 x = Rs. 120 cost price of the article = Rs. 120