Each of the articles is marked 80% above its cost price

Solution

If the MRP of article B is Rs. 1080. Cost price of article B of (100+80)% = 1080 Cost price of article B of 180% = 1080 1.8 x (Cost price of article B) = 1080 Cost price of article B = Rs. 600 Selling price of article B = 1080 of (100-30)% = 1080 of 70% = 1080 x 0.7 = Rs. 756 The selling price of article A is Rs. 126 less than the selling price of article B. selling price of article A = 756-126 =  Rs. 630 So Cost price of article A of (100+80)% of (100-30)% = selling price of article A Cost price of article A of 180% of 70% = 630 1.8x0.7x(Cost price of article A) = 630 1.26x(Cost price of article A) = 630 Cost price of article A = Rs. 500 difference between the cost price of article A and B = 600-500 = Rs. 100