sir thanks for the reply. but still not clear..Lets take numbers like n=3 so n(n+1)(n+1)= 3(4)(4)= 16*3= 48, which is multiple of 3 but if the number is n = 4 then n(n+1)(n+1)= 3(5)(5)= 25*3= 75= multiple of 3

Is it sounds nice with an example sir? Pls clarify

Pls clarify one thing again that n has to be in case above multiple of 3 which makes n-1 not multiple of 3. Ans to the statement would no and thus be the ans. pls confim

Note that statement (1) and (2) are very similar:

Statement (1)
(n - 1) n (n + 1), which are consecutive integers. So, (n - 1) n (n + 1) is a multiple of 3.
For any 3 consecutive integers, one of the 3 will always be a multiple of 3.

Statement (2)
n(n + 1)² = n (n + 1)(n + 1) is a multiple of 3. So, either n or (n + 1) is a multiple of 3.

From (n - 1) n (n + 1) we know that either n or (n + 1) is a multiple of 3. So the only one left is (n - 1) which will never be a multiple of 3, because the multiple of 3 will always lie (according to this statement) between n and (n + 1), and thus never in (n - 1). For example:

(2)*(3)*(4) = 24 (multiple of 3)
(1)*(2)*(3) = 6 (multiple of 3)

Hope it helps!