gmat prep question

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gmat prep question

by preetha_85 » Sun Jul 27, 2008 2:15 am
Hi

Can u help me solve this
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by ildude02 » Sun Jul 27, 2008 9:03 am
I'm not so sure about the question. I would have picked the choice as A and this will be my reasoning. Question says there are either 40 cows or 40 pigs(2/3 of 60)

statement 1 says, Cows are more in number(twice the number of pigs) than pigs. So basically, cows should be 40 and not pigs since if pigs were 40, then the cows should be 80 which would mean it will be greater than the 60 animals in the farm.

Seems like obviously the answer choice is C, so I'm not sure where the trick lies.

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by parallel_chase » Sun Jul 27, 2008 3:45 pm
Well the answer is C. This is very tricky question.

If you look at the Statement I it says:

The cows are more than twice the number of pigs. But we dont know the value of more.
Pigs could be 10 then cows would be 10 more than twice the number of pigs.
Similarly pigs could be any value between 1-13. I say 13 because if there are more than 13 pigs then this statement will have no meaning.Therefore insufficient.

Statement II pigs are more than 12. It does not tell us anything about the cows. Therefore Insufficient.

If you combine both the statements, first statement says pigs 1-13, seond statement says more than 12. Hence C is the answer.

Let me know if you still have any doubts.

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by parallel_chase » Sun Jul 27, 2008 3:50 pm
ildude02 wrote:I'm not so sure about the question. I would have picked the choice as A and this will be my reasoning. Question says there are either 40 cows or 40 pigs(2/3 of 60)

statement 1 says, Cows are more in number(twice the number of pigs) than pigs. So basically, cows should be 40 and not pigs since if pigs were 40, then the cows should be 80 which would mean it will be greater than the 60 animals in the farm.

Seems like obviously the answer choice is C, so I'm not sure where the trick lies.
I think you have misinterpreted the question, this question is from SETS theory.
The questions says 40 is a mixture of cows and pigs. lPUCl = 40

Hope this helps, let me know if you still have any doubts.

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by ildude02 » Sun Jul 27, 2008 3:59 pm
parallel_chase wrote:Well the answer is C. This is very tricky question.

If you look at the Statement I it says:

The cows are more than twice the number of pigs. But we dont know the value of more.
Pigs could be 10 then cows would be 10 more than twice the number of pigs.
Similarly pigs could be any value between 1-13. I say 13 because if there are more than 13 pigs then this statement will have no meaning.Therefore insufficient.
.
What's limiting from having the number of pigs greater than 13, as in 14? I would consider if pigs are 14, then the cows can be more than 28(since it's more than twice the pigs). There sum would still be less then the total of 60 number of animals.

I think there is a definite meaning to "2/3 of either pigs or cows". I'm not sure what that means in mathemtical term. I took that statement as , there are 40 pigs or 40 cows for sure. So, I was only lookign to find an asnwer that would help me make that decision as to which one is 40 in number. Obviously, that's the reason I took A as an answer since it says "cows" are more in number.

Well, apparently, I'm not able to interpret exactly what does "2/3 of either pigs or cows" mean here? If you could clarify that for me, I'd really appreciate it.

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by parallel_chase » Sun Jul 27, 2008 4:07 pm
What's limiting from having the number of pigs greater than 13, as in 14? I would consider if pigs are 14, then the cows can be more than 28(since it's more than twice the pigs). There sum would still be less then the total of 60 number of animals.
The number of cows and pigs cannot exceed 40, if you take 14 pigs the cows would be X more than 28. This itself cannot hold true because 14+28=42, therefore the number of pigs has to be less than 13 for this statement to hold true.

Kindly refer to my previous post for the explanation.

Let me know if you still have any doubts.

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by ildude02 » Sun Jul 27, 2008 4:16 pm
parallel_chase wrote:
ildude02 wrote:I'm not so sure about the question. I would have picked the choice as A and this will be my reasoning. Question says there are either 40 cows or 40 pigs(2/3 of 60)

statement 1 says, Cows are more in number(twice the number of pigs) than pigs. So basically, cows should be 40 and not pigs since if pigs were 40, then the cows should be 80 which would mean it will be greater than the 60 animals in the farm.

Seems like obviously the answer choice is C, so I'm not sure where the trick lies.
I think you have misinterpreted the question, this question is from SETS theory.
The questions says 40 is a mixture of cows and pigs. lPUCl = 40

Hope this helps, let me know if you still have any doubts.
This clarifies, I guess you posted this at the same time I was asking you to clarify it for me :). So, when we see " a or b", should we almost treat it as in AUB? Since technically, if we see the same question say, "2/3 are pigs and cows, I would have treated is like C+P = 40 . But if we consider it a set theory, wouldn't that mean "P intersection C"?

I always get trumped with the set related questions and it's mostly because I sometimes miss to interpret properly about the or, either and " meaning which is relevent to the question. Appreciate your input on this.

Thanks!

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by parallel_chase » Sun Jul 27, 2008 4:31 pm
So, when we see " a or b", should we almost treat it as in AUB? Since technically, if we see the same question say, "2/3 are pigs and cows, I would have treated is like C+P = 40 . But if we consider it a set theory, wouldn't that mean "P intersection C"?
For every "or" it is not advisable. In set theory you can do that but you also have to look at the context of question. Try not to generalize things, look at the logic behind everything. If you see this question on GMAT, statement "40 are either cows or pigs out of 60" and going by method 40 cows or 40 pigs should ring bells because the question says there are only 60 animals.

No it cannot be P intersection C because each set of pigs and cows are mutually exclusive.

In this question for P intersection C, they would most likely have to change the problem and statements.

Hope this clears everything.

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by preetha_85 » Sun Jul 27, 2008 8:11 pm
Hi

Thanks a lot everybody.