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Is Zero divisible 3????

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Saurabh Malpani
 Post subject: Is Zero divisible 3????
 Post Posted: Fri Apr 20, 2007 6:48 pm 
Is N*(N+1) divisible by 6

a) N is an even integer
2) N is divisible by 3


Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
EACH statement ALONE is sufficient
Statements (1) and (2) TOGETHER are NOT sufficient

My COncern:.

I don’t think the answer is correct WHY Didn’t we consider ZERO here isn’t zero divisible by 3??

Can't N=0?

Please respond this is a very Important Question
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Guest
 Post subject:
 Post Posted: Fri Apr 20, 2007 10:04 pm 
I don't know what answer is given to you. But I would go for (B)
Here's why:

* N is divisible by 3. Therefore for a non-zero N, (N + 1) is even and hence N*(N + 1) is divisible by (3*2) i.e. 6. If N = 0, N*(N + 1) = 0 and hence is still divisible by 6 (if 0 is divisible by 3, it is also divisible by 6). Sufficient
* N is even. Here (N+1) is odd, but not necessarily divisible by 3. e.g. if N = 4, N + 1 = 5 and N*(N + 1) is not divisible by 6. However, if N = 2, N + 1 = 3 and N*(N + 1) is divisible by 6. So, not sufficient
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Saurabh Malpani
 Post subject:
 Post Posted: Sat Apr 21, 2007 12:38 am 
Anonymous wrote:
I don't know what answer is given to you. But I would go for (B)
Here's why:

* N is divisible by 3. Therefore for a non-zero N, (N + 1) is even and hence N*(N + 1) is divisible by (3*2) i.e. 6. If N = 0, N*(N + 1) = 0 and hence is still divisible by 6 (if 0 is divisible by 3, it is also divisible by 6). Sufficient
* N is even. Here (N+1) is odd, but not necessarily divisible by 3. e.g. if N = 4, N + 1 = 5 and N*(N + 1) is not divisible by 6. However, if N = 2, N + 1 = 3 and N*(N + 1) is divisible by 6. So, not sufficient


Oh ho!!! I see where I was wrong, thank you very much!!! What a silly mistake...

Thanks a ton!!

Saurabh Malpani
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j_sibal
 Post subject: Re: Is Zero divisible 3????
 Post Posted: Sun Feb 20, 2011 5:14 am 
Offline
Students


Posts: 4
What about in the following case: is N(N+1)(N-1) divisible by 6?

1) N is a positive integer

2) N is divisible by 3

In this case can one consider 0 to be divisible by 6? (plugging in 1 in the first statement)
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RonPurewal
 Post subject: Re: Is Zero divisible 3????
 Post Posted: Tue Feb 22, 2011 7:17 am 
Offline
ManhattanGMAT Staff


Posts: 7146
j_sibal wrote:
What about in the following case: is N(N+1)(N-1) divisible by 6?

1) N is a positive integer

2) N is divisible by 3

In this case can one consider 0 to be divisible by 6? (plugging in 1 in the first statement)


heh, nice four-year bump.

yes, 0 is divisible by 6. in fact, 0 is divisible by EVERY positive integer.
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