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A certain list consists of several different integers.

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Guest
 Post subject: A certain list consists of several different integers.
 Post Posted: Fri Aug 15, 2008 8:36 pm 
A certain list consists of several different integers. Is the product of the all the integers in the list positive?

1. The product of the greatest and smallest integer in the list is positive.
2. There is an even number of integers in the list.

I thought that E is the answer. Each statement is insufficient by itslef. When combined, I can have 4 integers. Let's say the smallest and the largest are both positive. The two numbers in between can be either positive, or one negative and one positive, which makes the product either positive and negative. Therefore, answer E.

The OA is C. Can someone please point the error in my logic or suggest a solution to the problem?

Thanks
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San
 Post subject: Re: A certain list consists of several different integers.
 Post Posted: Fri Aug 22, 2008 1:50 am 
Anonymous wrote:
A certain list consists of several different integers. Is the product of the all the integers in the list positive?

1. The product of the greatest and smallest integer in the list is positive.
2. There is an even number of integers in the list.

I thought that E is the answer. Each statement is insufficient by itslef. When combined, I can have 4 integers. Let's say the smallest and the largest are both positive. The two numbers in between can be either positive, or one negative and one positive, which makes the product either positive and negative. Therefore, answer E.

The OA is C. Can someone please point the error in my logic or suggest a solution to the problem?

Thanks


That was exactly what I thought when I did that question on gmat prep. I also came out the answer with E. so far, I still have a hard time to convince myself the answer is actually C
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Guest
 Post subject:
 Post Posted: Fri Aug 22, 2008 9:37 am 
Instructors,

Would you please help to justify answer C?

Thank you.
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Dan
 Post subject:
 Post Posted: Fri Aug 22, 2008 10:43 am 
Think about it this way

1) If the list has an odd number of items: -3,-2,-1, it satisifies the condition that product of the lowest and greatest value is positive, but the product of all the integers is negative.
2) The list can be -3,-2,-1,0, which would result in a negative product. However, if we take into consideration #1, then we have: -4,-3,-2,-1. This will be positive.

Therefore the answer is C.
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Guest
 Post subject: Re: A certain list consists of several different integers.
 Post Posted: Sat Aug 23, 2008 6:39 am 
Anonymous wrote:
A certain list consists of several different integers. Is the product of the all the integers in the list positive?

1. The product of the greatest and smallest integer in the list is positive.
2. There is an even number of integers in the list.

The OA is C. Can someone please point the error in my logic or suggest a solution to the problem?

Thanks


Considering original answer i.e. C.

If we arrange the 4 sample numbers in their increasing order, there are only 2 possible combinations, i.e. all 4 numbers are either negative or as positive:
++++
----

Any other other combination is invalid because the smallest and the greatest integers must have the same sign to satisfy statement 1. The product of both these valid combinations is positive.

For further read on the same question, see the link below:
http://www.manhattangmat.com/forums/a-c ... t1002.html
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RonPurewal
 Post subject: Re: A certain list consists of several different integers.
 Post Posted: Wed Aug 27, 2008 6:28 am 
Offline
ManhattanGMAT Staff


Posts: 7146
Anonymous wrote:
Anonymous wrote:
A certain list consists of several different integers. Is the product of the all the integers in the list positive?

1. The product of the greatest and smallest integer in the list is positive.
2. There is an even number of integers in the list.

The OA is C. Can someone please point the error in my logic or suggest a solution to the problem?

Thanks


Considering original answer i.e. C.

If we arrange the 4 sample numbers in their increasing order, there are only 2 possible combinations, i.e. all 4 numbers are either negative or as positive:
++++
----

Any other other combination is invalid because the smallest and the greatest integers must have the same sign to satisfy statement 1. The product of both these valid combinations is positive.

For further read on the same question, see the link below:
http://www.manhattangmat.com/forums/a-c ... t1002.html


you know it's a good day when anonymous guest posters are providing cross-reference links to other forum posts.
awesome.

by the way, to you users out there who haven't poked around this forum much: we've gotten to the point where the vast majority of gmatprep problems are already the subject of at least one thread (and sometimes several threads) on the forum. it will be WELL worth your time to try the search box before posting a new thread; not only will we not have to waste the time posting cross-references, but you'll also get your feedback within seconds instead of waiting for reply posts.
warning: the search box can be obstreperous, so try several different combinations of keywords before concluding that a problem is absent from the forum.
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