A sold an article with 10 percent loss on the cost price. He bought the article at a discount of 20 percent on the labeled price. What would have been the percentage loss had he bought it at the labeled price ?

Let the marked price be INR 100/-

∴ C.P. = 80/100 × 100

         = INR 80/-

S.P. = 80/100 × 90

       = INR 72/-

If he bought at marked price i.e. INR 100/-

∴ Loss = 100-72 = INR 28/-

∴ Loss Percentage = 28/100 × 100

                            = 28%