Advanced GMAT Quant Page. 77

[andrew.hyung]

Is the integer n odd?
1) n^2 - 2n is not a multiple of 4
2) n is a multiple of 3

I understand why (2) is insufficient, but the explanation provides that (1) is sufficient.
Although every integer greater than 2 is sufficient, 2 itself will make the answer insufficient.

Am I wrong?

Thanks in advance.

[smohit04]

We can re-write option as:

n(n-2)

Thus if n is Even: E(E-2) will be a multiple of 4
if n is Odd: O(O-2) will be Odd and not a multiple of 4

For n=2, n(n-2)=0 which is again a multiple of 4 (4x0=4)

[jnelson0612]

Is the integer n odd?
1) n^2 - 2n is not a multiple of 4
2) n is a multiple of 3

I understand why (2) is insufficient, but the explanation provides that (1) is sufficient.
Although every integer greater than 2 is sufficient, 2 itself will make the answer insufficient.

Am I wrong?

Thanks in advance.

Actually, if I use n=2, I get (2)^2 - 2(2) which is 4 - 4, or 0. Zero IS a multiple of all integers, so it is also a multiple of 4. Thus, we cannot use 2 as a value for n since this result does not match our statement.