A shopkeeper sells an item at 12.5 profit and also uses a false weight of 1100 grams instead of 1200 grams. Find his overall profit percentage

Shopkeeper earns 12.5% profit on marked price. Additionally, he gives only 1100g instead of 1200g, gaining an extra 100g on every 1100g sold, which is (100/1100) × 100 = 9.09% profit. Total profit = (1 + 12.5/100) × (1 + 9.09/100) - 1 = 1.125 × 1.0909 - 1 = 1.2272 - 1 = 22.72%. Alternatively, using the formula: (Profit% + False gain% + (Profit% × False gain%)/100) = 12.5 + 9.09 + (12.5×9.09)/100 = 22.72%.