10% discount and then 20% discount in succession is equivalent to total discount of .

Two successive discounts of 10% and 20% on an article are equivalent to a single discount of x%.What is X?

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

The value of a single discount on some amount which is equivalent to a series of discounts of 10%, 20% and 40% on the same amount, is equal to