The sum of cost price and marked price of article 'A' and that of article 'B' are Rs. 11,000 and Rs. 18,000, respectively. Articles 'A' and 'B' were marked 20% and 50% above their respective cost prices. If both the articles were sold after allowing a discount of 25%, then find the difference between their selling prices.

Let the cost price of article 'A' be Rs. 'x' Therefore, marked price of article 'A' = 1.20 × x = Rs. '1.2x' According to the question, 1.2x + x = 11000 Or, 2.2x = 11000 Or, x = (11000 / 2.2) = 5000 Marked price of article 'A' = 1.2 × 5000 = Rs. 6000 Selling price of article 'A' = 0.75 × 6000 = Rs. 4500 Similarly, let the cost price of article 'B' be Rs. 'y' Marked price of article 'B' = 1.5y y + 1.5y = 18000 Or, 2.5y = 18000 Or, y = (18000 / 2.5) = 7200 Marked price of article 'B' = 1.5 × 7200 = Rs. 10800 Selling price of article 'B' = 0.75 × 10800 = Rs. 8100 Required difference = 8100 − 4500 = Rs. 3600