Profit and Loss - General Questions

A shopkeeper marks his goods 20% above the cost price and allows a discount of 25%. What is his gain percent?

A man sells two articles at the same price. On one he gains 25% and on the other he loses 25%. What is his overall gain or loss percent?

The cost price of 31 articles is equal to the selling price of 23 articles. What is the gain percent?

The cost price of 29 articles is equal to the selling price of 23 articles. What is the gain percent?

An article bought for Rs. 580 is sold for Rs. 652.5. What is the gain percent?