A shopkeeper sells goods at the cost price but uses a 500 g weight in place of a 1 kg weight. What is the gain percentage?

💡 Solution & Explanation

The buyer pays for 1,000 g but receives only 500 g. So the seller gains 500 g on every 500 g actually given. Gain % = (500 ÷ 500) × 100 = 100%. Dividing by 1,000 instead gives 50%, which is wrong because the cost is for the 500 g handed over.