When a discount of `10%` is given on markled price,the gain of trader is `20%` What will be profit percentage,if a discount of `13%` is given?

If a discount of 10% is given to a customer on the marked price of an article, the gain of the trader is 20%. What will be the gain per cent of the trader if the discount is increased to 15%?

After giving 40% discount on an article there is still a profit of 20%. What will be the profit percentage when no discount is given?

A series discount of 20%,10% is equivalent to a single discount of