IanStewart wrote:
fskilnik wrote:
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.
There is such a restriction, and for a good logical reason. Imagine the following DS question:
What is the value of x?
1. Either x=3 or x=4
2. Either x=5 or x=6
What is the answer to this DS question? It would be perfectly reasonable to say "using both statements,
no value of x exists, so I've answered the question and the answer is C". But it would be just as reasonable to say "using both statements, I can't solve the question because no value of x exists, so the answer is E". There is no logically correct answer to this question.
So it always must be true in any DS question that the two statements are logically consistent - it needs to be possible for both statements to be true simultaneously, since sometimes test takers will combine the statements. If the statements are not consistent, then you can have situations where a question has two perfectly justifiable 'correct' answers, which is obviously something that can't happen on the GMAT.
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?
Quote:
But it would be just as reasonable to say "using both statements, I can't solve the question because no value of x exists, so the answer is E".
• 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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