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Do the official DS Qs use the "no" answer as unique and sufficient?

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iliavko
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Do the official DS Qs use the "no" answer as unique and sufficient? [#permalink] New post   17 Jan 2017, 08:25
Hi everyone!

A question on DS here.

Is y > 0?

(1) x^2 − y^2 = 0

(2) x^2 + y^2 = 0

The answer is B, because the statement gives a NO answer.

My question: do the real questions have the "definitively NO" as a possible outcome? Or should we always aim for the "absolutely YES" answer?

There are many prep companies that have these def-NO questions and since we get a unique NO answer it's sufficient, but I have never seen an OG question "aiming" for a def-NO answer. They all seem to be tuned to be proven "True, YES" and not proven "NO"

Do I make myself clear here?

Cheers!
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ccooley
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Do the official DS Qs use the "no" answer as unique and sufficient? [#permalink] New post   17 Jan 2017, 13:47
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Both "always no" and "always yes" are sufficient. On a yes/no problem, a statement is only sufficient if it gives you information that lets you sometimes answer yes and sometimes answer no. That is, you have to get both a 'yes' answer and a 'no' answer to prove that a statement is insufficient.

Your example question is a valid GMAT question and would have an answer of B.
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Re: Do the official DS Qs use the "no" answer as unique and sufficient? [#permalink] New post   17 Jan 2017, 14:46
Hi ccooley !

Thank you for your reply. What I meant by my question is, will the official questions ever have "always no" as an answer? or the official ones will have "only yes" only? I am asking because I have never seen an official Q that would have "always no" The official ones always lead to "always yes"

So on the real thing should we even consider that the answer may be "always no" ?
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Re: Do the official DS Qs use the "no" answer as unique and sufficient? [#permalink] New post   17 Jan 2017, 16:00
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iliavko wrote:
Hi ccooley !

Thank you for your reply. What I meant by my question is, will the official questions ever have "always no" as an answer? or the official ones will have "only yes" only? I am asking because I have never seen an official Q that would have "always no" The official ones always lead to "always yes"

So on the real thing should we even consider that the answer may be "always no" ?


Well, I went looking for examples that had an 'always no' statement, and I couldn't find any in the most recent OG. :) So I asked around, and it turns out that there were some like this in previous OGs, but there might not be any in the 2017 version (so please let me know if you find one.) Even still, I wouldn't assume this could never happen on the official test, unless the GMAC says something about it.
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Re: Do the official DS Qs use the "no" answer as unique and sufficient? [#permalink]
17 Jan 2017, 16:00
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