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A certain list consists of several different integers. Is

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Senior Manager
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29 Jul 2007, 12:21
I get C on this one.

from statement 1, the list can be -2, -5, -10. or 2, 5, 10. (but the smallest and the biggest must be positive, so -2, 4, 5, 10 wouldn't work with this)

from statement 2, the list has to be even. -2, 1, 3, 5 or -2, -4, -5, -10 or 1, 2, 4, 5

Neither is sufficient on its own.

Combined, we see its C, or at least to me it is
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07 Jun 2009, 10:24

1. Insufficient.Implies, either both smallest and largest are +ve nos or both are -ve nos.
• If both smallest and largest +ve
All integers would be +ve, hence product also +ve
• If both smallest and largest +ve,
All integers in the list would be -ve. Product would be +ve, only if there are even no. of integers in the list

2. Insufficient.Even no. of integers. But we don't know how many are +ve or -ve, so cannot conclude anythig.

Together. Sufficient.
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07 Jun 2009, 10:33
Ah, right. I kept getting hung up on the fact that we do not know if 0 is in the list or not, but from stat 1, we should be able to conclude that 0 isnt in the list because the only options are all negative integers, or all positive.
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Re: Stuck with an easy number property....:( [#permalink]

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09 Jun 2009, 09:19
joyseychow wrote:
A certain list consists of several different integers. Is the product of all the integers in the list positive?

(1) The product of the greatest and smallest of the integers in the list is positive

(2) There is an even number of integers in the list

I think C

1) they could be all + or all -
insuff

2) list could include 0
insuff

together
either all + or all -, 0 excluded...even number of integers so product has to be positive
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Re: Stuck with an easy number property....:( [#permalink]

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09 Jun 2009, 09:37
I think, the answer should be Neither 'A' nor 'B', nor 'A + B',
Because 0 can also be a part of the list, then the product would come out to be 0 which is neither a positive nor a negative integer.
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09 Jun 2009, 12:14
because the possibility of 0 isnt eliminated in either statement, my answer is E.
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Re: Stuck with an easy number property....:( [#permalink]

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09 Jun 2009, 12:22
but statement 1 says that the product of the greatest * smallest is positive, i.e both neg or both pos, so 0 cant be included
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Re: Stuck with an easy number property....:( [#permalink]

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09 Jun 2009, 12:29
bigtreezl wrote:
but statement 1 says that the product of the greatest * smallest is positive, i.e both neg or both pos, so 0 cant be included

Youre absolutely right, I totally messed that up !
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Re: Stuck with an easy number property....:( [#permalink]

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09 Jun 2009, 20:35
Oh..yes..! even I missed that too.
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Re: integers in a list positive [#permalink]

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09 May 2011, 21:16
a set can be (2,3,4) or (-4,-3,-2) product is positive and negative in these cases. Not sufficient.

b set can be (0,2) or (-2,0,1,2) where product is neither positive nor negative. And for set (1,2) its positive.Not sufficient.

a+b gives (1,2,4,5) its positive.

(-1,-2) is positive too.
Also the set can't have 0 as its element as product of highest and lowest digits is positive meaning - (-2,-1,0,2) is not possible.

Hence C.
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Re: Is the product of all integers in the list positive? [#permalink]

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04 Jun 2011, 15:28
Good question

1. Not Sufficient

lets say there are 3 numbers in the sequence.
if the second number is positive then product of three would be positive.

if the second number is negative then product of three would be negative.

2. Not sufficient

without knowing the sign of the individual numbers , its not possible to find the sign of the product.

together ,

Its sufficient

lets say there are 4 numbers in the sequence. it could be like

-5 -4 -3 -2 product is positive
1 2 3 4 product is positive
...
....

Re: Is the product of all integers in the list positive?   [#permalink] 04 Jun 2011, 15:28

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