A 4 digit number which when divided by 12 16 and 18 gives out a common remainder i e 21 Find t...........

Explanation:

Here least possible 4 digit number is needed that means we need the LCM
We must first find LCM of 12, 16, 18 and 20
∴ LCM = 720
Now this is a 3 digit number.
If we multiply it by 2 we get (720 x 2) = 1440 → (4 digit number)
But 1440 is divisible by 12, 16, 18 and 20
We must have 21 as remainder, as per given condition.
So, Number = 1440 + 21 = 1461