If a businessman gives 15% discount on the marked price of his goods, then what percentage price does he get on the goods?

A businessman allows a discount of 10% on the marked price. What percent above the cost price must he mark his goods to make a profit of 17 per cent ?

A businessman allows a discount of 10% on the written price. How much above the cost price must he mark his goods to make a profit of 17% ?

A tradesman allows a discount of 15% on the marked price. How much above the cost price must he mark his goods as to gain 19%?