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Question Stats:
0% (00:00) correct
 0% (00:00) wrong based on 0 sessions
Is \frac{4Q}{11} a positive integer? 1. Q is a prime number 2. 2Q is divisible by 11 Source: GMAT Club Tests - hardest GMAT questions
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Manager
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B.
The question is asking whether Q is a multiple of 11.
1) Q as a prime number does not help us in answer the question.
INSUFF
2) 2Q is a multiple of 11, so 4Q should also be a multiple of 11.
SUFFICIENT
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Director
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yuefei wrote: B.
The question is asking whether Q is a multiple of 11.
1) Q as a prime number does not help us in answer the question.
INSUFF
2) 2Q is a multiple of 11, so 4Q should also be a multiple of 11.
SUFFICIENT
I got the same answer but that is not the OA.
Guys, any other answers?
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Manager
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I think the answer is C.
The reason is the question is asking if 4Q/11 is a +ive integer. 2Q/11 is divisble by 11 but it can be -ive also.
Any other thoughts please.
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Director
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smily_buddy wrote: I think the answer is C.
The reason is the question is asking if 4Q/11 is a +ive integer. 2Q/11 is divisble by 11 but it can be -ive also.
Any other thoughts please.
There is the missing link. You are right. That is why we need both conditions. (C) is the OA.
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VP
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1. prime number, it can give us a non integer
2. can be negative and positive
applied together 1 and 2. we say that prime cannot be negative and 2 gives us multiple so C
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GMAT Club Legend
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St1:
If Q = 11, then 4Q/11 is a positive integer.
If Q = 2, then 4Q/11 is not a positive integer.
Insufficient.
St2:
2Q/11 = integer.
If Q = 22, then 2Q/11 = integer and 4Q/11 = positive integer
if Q = -33/2, then 2Q/11 = integer but 4Q/11 != positive integer.
Insufficient.
St1 and St2:
Q = 11, then 2Q/11 = integer and 4Q/11 = positive integer.
Sufficient.
Ans C
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Ravshonbek wrote: 1. prime number, it can give us a non integer
2. can be negative and positive
applied together 1 and 2. we say that prime cannot be negative and 2 gives us multiple so C Little confused guys, prime numbers cannot be negative ? It means -11 is not qualified as a prime number ?
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Re: Math DS (m05q29) [#permalink]
 25 Oct 2009, 10:45
eyunni wrote: Is 4Q/11 a positive integer?
(1) Q is a prime number
(2) 2Q is divisible by 11 1: Q could be 2 or 3 or 5 or 7 or 11 or 13. NSF.. 2: Q could be -ve, 0 or +ve. For ex: -11 or -5.50 or 0 or 5.50 or 11 or any multiples of 11. NSF.. 1&2: Q must be a prime and 2Q must be divisible by 11. Q must be a prime eliminates the chances that Q is a -ve, 0 and fraction. Given that Q is a prime and 2Q must be divisible by 11 eliminate the chances that Q is other than 11. Therefore Q = 11 and 4Q/11 is a +ve integer i.e. 4. Thats a good question though....
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Re: Math DS (m05q29) [#permalink]
29 Nov 2009, 08:16
Hey I know I'm joining this thread really really late - but can anyone confirm whether prime numbers can be negative?
I checked the Wikipedia Prime page (I can't post the link!) but I didn't see anything definitive.
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Re: Math DS (m05q29) [#permalink]
26 Jun 2010, 10:16
http://mathforum.org/library/drmath/view/55940.html- Explanation as to why there are no negative prime numbers.
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Re: Math DS (m05q29) [#permalink]
26 Jun 2010, 18:12
C
1) Q can be 11 => it works or Q can be 3 => is not good, hence insufficient
2) 2Q is divisible by B, but we don't know if the result of this division is a positive integer, hence insufficient
1 & 2 together work
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Re: Math DS (m05q29) [#permalink]
15 Apr 2012, 13:53
eyunni wrote: Is \frac{4Q}{11} a positive integer? 1. Q is a prime number 2. 2Q is divisible by 11 Source: GMAT Club Tests - hardest GMAT questions (1) q is a prime number --> if q=2 then the answer is NO but if q=11 then the answer is YES. Not sufficient. (2) 2q is divisible by 11 --> \frac{2q}{11}=integer --> 2*\frac{2q}{11}=\frac{4q}{11}=2*integer=integer, but we don't know whether this integer is positive or not: consider q=0 and q=11. Not sufficient. (1)+(2) Since q is a prime number and 2q is divisible by 11, then q must be equal to 11 (no other prime but 11 will yield integer result for \frac{2q}{11} ) --> \frac{4q}{11}=4. Sufficient. Answer: C.
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Re: Math DS (m05q29)
[#permalink]
15 Apr 2012, 13:53
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