On dividing a certain number by 342 we get 47 as remainder.If same number is divided by 18, what will be the remainder?

Let the Number be X and when X is divided by 342 we get Quotient Q.

Now Our Number = 342*Q+47
Number = 18 X 19Q + 18 X 2 + 11
Number = 18 X (19Q + 2) + 11

So the number when divided by 18 gives 11 as remainder.

Shortcut : Divide 47(remainder) by 18(new number) and remainder is your answer.