By selling 60 meters of cloth,a merchant gains as a profit the cost of 15 meters.His gain per cent is

Find his gain per cent.

By selling 50 metres of cloth, a person gains the cost price of 20 metres of cloth. What is his gain percent?

By selling 60 articles a vendor gains the selling price of 15 articles . Find his gain percentage.

By selling 130 cassettes,a man gains an amount equal to the selling price of 5 cassettes.Find the gain per cent.