I assume that the first statement is (P^3)/3...
1. Cube of even number is always even (even*even*even = even) whereas cube of an odd number is always odd (odd*odd*odd = odd). If (P^3)/3 is odd then (P^3) will be also odd ( multiplying with odd 3). If (P^3) is odd then P will also be odd. SUFFICIENT
2. P is not divisible by 6 does not tell anything about P in terms of even/odd. 5 is odd and not divisible by 6, 4 is even and not divisible by 6. INSIFFICIENT
Is P an even or an odd ?
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AleksandrM
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I agree, the answer should be A. P must be either 3, 9, 27, or some other multiple of 3. The second statement doesn't even point you in that direction.
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lunarpower
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important - does the question specify that p is an integer? if not, then there are non-integral solutions satisfying (1) that, because they are not integers, are not odd.amitansu wrote:Is P an even or an odd ?
1. P^3/3 is odd
2. P^2 is not divisible by 6
for instance, let p be the cube root of 15. then (p^3)/3 = 15/3 = 5, which is certainly odd, but p itself is not odd (because it's not an integer at all).
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if the problem does specify that p is an integer, then simplyjat's analysis is right on.
Ron has been teaching various standardized tests for 20 years.
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simplyjat
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Yeah, after Ron's post I realized that the question never mentions P as an integer. Thanks Ron for correcting me.lunarpower wrote:important - does the question specify that p is an integer? if not, then there are non-integral solutions satisfying (1) that, because they are not integers, are not odd.amitansu wrote:Is P an even or an odd ?
1. P^3/3 is odd
2. P^2 is not divisible by 6
for instance, let p be the cube root of 15. then (p^3)/3 = 15/3 = 5, which is certainly odd, but p itself is not odd (because it's not an integer at all).
--
if the problem does specify that p is an integer, then simplyjat's analysis is right on.
simplyjat
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Stuart@KaplanGMAT
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This particular question (in the form provided) would never appear on the GMAT.
"Is P an even or an odd", is technically asking "is P an integer?" At best, the question could have two possible interpretations (another reason why it wouldn't appear as written).
Remember, the answer to an "is" question is going to be yes (sufficient), no (sufficient) or maybe (insufficient).
So, if P is an integer, then it is DEFINITELY "an even or an odd". If P is NOT an integer, then it is DEFINITELY NOT "an even or an odd". If P sometimes is an integer and sometimes isn't, then P MIGHT be "an even or an odd".
My guess is that the poster really meant to address the question "Is P even" or "Is P odd", which is how this question would be written on the real GMAT. It's even likelier that the question would have specified that P was in fact an integer (since on the vast majority of GMAT even/odd questions, fractions are taken out of the picture).
"Is P an even or an odd", is technically asking "is P an integer?" At best, the question could have two possible interpretations (another reason why it wouldn't appear as written).
Remember, the answer to an "is" question is going to be yes (sufficient), no (sufficient) or maybe (insufficient).
So, if P is an integer, then it is DEFINITELY "an even or an odd". If P is NOT an integer, then it is DEFINITELY NOT "an even or an odd". If P sometimes is an integer and sometimes isn't, then P MIGHT be "an even or an odd".
My guess is that the poster really meant to address the question "Is P even" or "Is P odd", which is how this question would be written on the real GMAT. It's even likelier that the question would have specified that P was in fact an integer (since on the vast majority of GMAT even/odd questions, fractions are taken out of the picture).
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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simplyjat
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Stuart, I second your opinion here with respect to the possibility of such questions in GMAT. I also personally feel that these type of question will not appear in GMAT. It's illogical to penalize the test taker for a logical assumption. This specific question is not looking for intelligence, but attention to detail.
I have never seen such a question anywhere, in sets, in OG or whatever other source that is available to me. But these kind of questions are filled in MGMAT. I have seen a lot of these question in 6 MGMAT online tests. Until and unless we have any of such questions backed by GMAC explanation, we will be divided.
I am not sure whether MGMAT online test are helping us or ruining our GMAT score. Because the absence or presence of the assumption makes a lot of difference.
I have never seen such a question anywhere, in sets, in OG or whatever other source that is available to me. But these kind of questions are filled in MGMAT. I have seen a lot of these question in 6 MGMAT online tests. Until and unless we have any of such questions backed by GMAC explanation, we will be divided.
I am not sure whether MGMAT online test are helping us or ruining our GMAT score. Because the absence or presence of the assumption makes a lot of difference.
simplyjat
