Hi,
I have a question regarding DS questions.
If the choice, either (1) or (2), gives an answer to a specific question, being YES or NO, should I choose it because it gives a specific answer, or because the answer it gives is YES?
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- Valerieangelkos
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I'm not 100% sure I understand your question.
Everything comes down to whether or not a statement provides enough information to answer a target question with absolute certainty.
So, for example, if the target question is a YES/NO question, as in "Is k a prime number?", then we need to determine whether or not a statement provides enough information to state either "yes, k is definitely a prime number or "no, k is definitely not a prime number." If we can definitively answer the question (either yes or no), then the statement is sufficient.
If the target question is a VALUE question, as in "What is the value of k?", then we need to determine whether or not a statement provides enough information to state "the value of k must be ...... " If we can do this, then the statement is sufficient.
For more information about this, you might want to watch our free video that covers this particular question: https://www.gmatprepnow.com/module/gmat- ... cy?id=1098
Cheers,
Brent
Everything comes down to whether or not a statement provides enough information to answer a target question with absolute certainty.
So, for example, if the target question is a YES/NO question, as in "Is k a prime number?", then we need to determine whether or not a statement provides enough information to state either "yes, k is definitely a prime number or "no, k is definitely not a prime number." If we can definitively answer the question (either yes or no), then the statement is sufficient.
If the target question is a VALUE question, as in "What is the value of k?", then we need to determine whether or not a statement provides enough information to state "the value of k must be ...... " If we can do this, then the statement is sufficient.
For more information about this, you might want to watch our free video that covers this particular question: https://www.gmatprepnow.com/module/gmat- ... cy?id=1098
Cheers,
Brent
- fcabanski
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The statement is sufficient if it answers the question. If the question is a yes/no question, and the statement lets you know the answer is no, then the statement is sufficient.
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- ceilidh.erickson
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A definitive YES or a definitive NO answer would each be sufficient. Only an answer of MAYBE (or "sometimes yes, sometimes no") would be insufficient.
However, "definitive NO is sufficient" is not a rule that the GMAT tests regularly. For most YES/NO questions, a statement that gives sufficient information will give a "yes" answer to the question.
Out of the DS problems in OG13 and the Quant Supplement 2nd Ed, only 1 that I can find has statements that give a definitive "no" answer:
We can rephrase the question as "does the operation @ represent multiplication?" as multiplication is the only operation for which k @ (L + m) = (k @ L) + (k @ m)
(1) k @ 1 is not equal to 1 @ k for some numbers k.
If these two are not equal, then @ must NOT represent multiplication, because k*1 = 1*k. Therefore, the answer to the question "is @ multiplication?" is "no, definitely not." Sufficient.
(2) @ represents subtraction.
Again, the answer to the question "is @ multiplication?" is "no, definitely not." Sufficient.
The answer is D.
However, "definitive NO is sufficient" is not a rule that the GMAT tests regularly. For most YES/NO questions, a statement that gives sufficient information will give a "yes" answer to the question.
Out of the DS problems in OG13 and the Quant Supplement 2nd Ed, only 1 that I can find has statements that give a definitive "no" answer:
(The actual problem used a circle, not an @ symbol, but I don't know how to recreate that here!)DS #136 OG13
If @ represents one of the operations +, -, and x , is k @ (L + m) = (k @ L) + (k @ m) for all numbers k, L , and m ?
(1) k @ 1 is not equal to 1 @ k for some numbers k.
(2) @ represents subtraction.
We can rephrase the question as "does the operation @ represent multiplication?" as multiplication is the only operation for which k @ (L + m) = (k @ L) + (k @ m)
(1) k @ 1 is not equal to 1 @ k for some numbers k.
If these two are not equal, then @ must NOT represent multiplication, because k*1 = 1*k. Therefore, the answer to the question "is @ multiplication?" is "no, definitely not." Sufficient.
(2) @ represents subtraction.
Again, the answer to the question "is @ multiplication?" is "no, definitely not." Sufficient.
The answer is D.
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
EdM in Mind, Brain, and Education
Harvard Graduate School of Education