A cloth merchant sold half of his cloth at 40% profit, half of remaining at 40% loss and the rest was sold at the cost price. In the total transaction his gain or loss will be = ?

let there is 100 stock with price cost price Rs. 100.
Total cost is 100 × 100 = Rs. 10000
∴ 50 item sold at price 40% profit
i.e = 140 × 50 = Rs. 7000
⇒ 25 item sold at price 40% loss
i.e = 60 × 25 = Rs. 1500
⇒ And remaining 25 item sold at cost price
i.e = 100 × 25 = Rs. 2500
∴ total sell price is 7000 + 1500 + 2500 = Rs. 11000 (profitable)
∴ Profit% is 10% gain