A dishonest shopkeeper sold his goods at 10% loss and he used 750 gm in place of 1 kg. Find the profit or loss percentage.

Let the price of the goods is Rs. 1 per gm.

Then, CP of 1000 gm = Rs. 1000

Shopkeeper sold the goods at 10% loss

⇒ SP of 1000 gm goods = Rs. 900

He also uses 750 gm weight instead of 1000 gm

⇒ He sold the goods at Rs. 900 instead of Rs. 750

Profit = 900 – 750 = Rs. 150

Profit % = (150/750) × 100 = 20%

∴ Shopkeeper makes a profit of 20%.