Hi jasmitkalra ..... welcome to the community.

The answer is no. You are definitely not going to see such Qs in any GMAT real test.
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This will never happen on the GMAT. You might see unofficial questions that behave like this - if so, that question is poorly written!

Since you know that this will never happen on the real GMAT, you can actually take advantage of that knowledge on certain problems. For instance, suppose that you're solving this problem:

Is x positive?
(1) x = 2
(2) |x|-x/2 > 0

The first statement is easy - you know x is positive. So that's sufficient. The second statement, you might notice right away that x could be negative. You actually don't have to keep testing cases at this point! Once you know that x could be negative, you know that this statement is insufficient. That's because the statements won't contradict each other: it'll never be the case that (1) says x is always positive, but (2) says x is always negative. The only possibility is that (1) says x is always positive, but (2) says that it could go either way. So the answer would be (A).
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One important question to Bunuel, ccooley,
Here is an example:

Is x positive?
1) definite yes
2) i have no idea
My question: statement 2 may give us only "yes" (but not "no" alone) or both yes and no simultaneously. As far we know that statement 1 and statement 2 can't contradict each other. So, why do we try to find out "yes" from statement 2 since we already know that statement 1 gives only "yes"?
Thanks__

Posted from my mobile device
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If you have a definite YES from (1), it means that it's sufficient. Now, (2) can give YES too, which would mean answer D, OR sometimes YES, sometimes NO, which would mean answer A. (2) cannot give a NO answer in this case because it would mean that (1) and (2) contradict each other.
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The two statements never contradict each other in official questions. This question seems to be poorly written. What's the source?
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Hi Bunuel,
did you miss my question?
or, is my question weird?
I think, my question is a pertinent point for knowing DS!
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Dear AsadAbu ,

You have asked (through a private message) our position on this matter.

This is a delicate issue (I have already exchanged posts with other experts on this matter) because "each statement alone is sufficient to answer the question asked" does NOT guarantee, by itself, that the unique answers obtained in each statement must be the same. I mean, logically speaking, there is not such a restriction. (The consideration of a "unique universe for both statements and the question stem pre-statements" is not explicitly mentioned in the Data Sufficiency official rules. In other words, this is not a "law" to be obeyed, it is one possible interpretation that one may decide to follow.)

On the other hand, it´s highly improbable that you will find any OFFICIAL GMAT quantitative section question in which the correct answer is D and in which each statement does not have the same unique answer as the other statement unique answer. The expression in bold was used by an official GMAT representative when I (myself!) made exactly the same question to her many years ago.

In short: in the official exam (i.e., where it matters), you may expect the same answers when each statement alone is sufficient to answer the question asked.

Regards,
Fabio.

P.S.: in my PERSONAL opinion, "same answers" (when (D) is correct) is much more elegant. I do NOT want to go into this any further. Please respect that.
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So, what is the answer of this DS according to GMAC?
Thanks__
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The example shown does not apply. All the issue is related to a DS question in which the right answer is (D). It´s not the case here, because each statement alone is NOT sufficient to answer the question asked (in a unique way).


According to DS rules, when it is questioned "what is the value of x?" , we must consider a statement sufficient if, and only if, the statement gives us only one answer, in this case, a unique numerical answer.
If each one alone is not sufficient, THEN AND ONLY THEN we must consider both statements together and, in your scenario, the fact that there is no value of x that satisfies both statements together implies that the problem must be considered wrong, in other words, it is not well-stated, in other words, there is no answer. Not C, Not E, Not A, Not B and Not D.


Yes, this is a nice argument for the "elegancy" I mentioned. Unfortunately it is a strong argument but, IN MY OPINION, not a "smocking gun". Please respect that.
I repeat: I wish I had a conclusive remark to save the day or, of course, I would like YOU to have one. Till now, I couldn´t have one that would close the matter according to MY level of rigor, so to speak.


In the case in which (D) is the right answer, we would have finished the problem before any logical trouble starts. But, again, I agree your vision is the nicer, because if we agree on your terms, alternative choice (D) does not have a "special treatment". In terms of "symmetry beauty", the Oscar goes to your argument. No doubt!

Well, nice discussion Ian. It´s a pleasure to see you are still active!

Kind Regards,
Fabio.
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Hi IanStewart,
Thanks for your creative example, but I have still some confusion in your explanation. I'll be really grateful if you eradicate my confusion.
In the highlighted part, could you tell me how did you get C, please? No value doesn't mean that it is sufficient, because sufficient means I've enough information to narrow THE QUESTION down to ONE ANSWER!. So, did you find one specific value/ONE ANSWER by combining both statements?


• When statement 1 sufficient then it is A
• When statement 2 sufficient then it is B
• When statement 1 & 2 Separately sufficient then it is D
• When statement 1 & 2 (after combining) sufficient then it is C
• But, E doesn't mean something is sufficient; actually E means C is insufficient/not sufficient!
So, in your example, C is insufficient/not sufficient (meaning we can't get one specific value for this question stem). So, the answer of your example is E to me.

One most important thing about the definition of insufficient/not sufficient is: So far I know insufficient/not sufficient doesn't mean the following :
• not good enough
• I can't solve
• need more info
• I don't know
Insufficient/not sufficient means: There are TWO OR MORE POSSIBLE ANSWERS to THE QUESTION.
So, what is your thinking in my explanation?
Thanks__
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