Profit and Loss - General Questions

A dishonest dealer professes to sell his goods at cost price but uses a weight of 950 g for a kilogram. What is his gain percent?

A shopkeeper marks his goods 20% above the cost price and allows a discount of 15%. What is his gain percent?

The cost price of 26 articles is equal to the selling price of 24 articles. What is the gain percent?

A man sold an article for Rs. 1,305 at a loss of 25%. What was the cost price?

A man sold an article for Rs. 1,216 at a loss of 20%. What was the cost price?