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If x and y are both positive integers, what is their greatest common
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11 Oct 2016, 02:13
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26% (01:01) correct 74% (00:54) wrong based on 152 sessions
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If x and y are both positive integers, what is their greatest common factor? (1) x and y are prime numbers. (2) x and y share only one common divisor.
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Re: If x and y are both positive integers, what is their greatest common
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11 Oct 2016, 05:02
Bunuel wrote: If x and y are both positive integers, what is their greatest common factor?
(1) x and y are prime numbers.
(2) x and y share only one common divisor. To find the GCD, we need to prime factorization. Stat 1: Clearly insufficient...as we don't have x and y values...only they are prime... Stat 2: Sufficient... Note : Every common divisor of a and b is a divisor of GCD (a, b)....in our case common division of x and y is a divisor of GCD(x,y).. IMO option B.



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Re: If x and y are both positive integers, what is their greatest common
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11 Oct 2016, 08:51
Stat 1 : any two prime nos share only one common divisor ,that is 1 sufficient
stat2 : every number has 1 as common divisor, since the statement says, one common divisor, GCD is 1 sufficient
IMO D



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If x and y are both positive integers, what is their greatest common
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11 Oct 2016, 09:34
mohshu wrote: Stat 1 : any two prime nos share only one common divisor ,that is 1 sufficient
stat2 : every number has 1 as common divisor, since the statement says, one common divisor, GCD is 1 sufficient
IMO D Your stat 1 is incorrect. If you take x and y are 2 and 3 respectively...then GCD is 1 if x and y are both 3 and 3...then GCD is 3.... It is not mentioned that x and y are not equal... Hope this clears..



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Re: If x and y are both positive integers, what is their greatest common
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12 Oct 2016, 13:48
If x and y are both positive integers, what is their greatest common factor?
(1) x and y are prime numbers.
(2) x and y share only one common divisor.
My answer is (d), both statements are sufficient, because 2 prime numbers will have one common divisor that is 1. The second statement also means 1 is a common advisor, so both are sufficient.



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Re: If x and y are both positive integers, what is their greatest common
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12 Oct 2016, 14:22
Even I thought the answer is D.
But, the only reason I can think of D not being the correct answer choice, is no where in the question it being mentioned that they are "Distinct" +ve integers.
Any one who can clarify?



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Re: If x and y are both positive integers, what is their greatest common
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12 Oct 2016, 14:24
msk0657 wrote: mohshu wrote: Stat 1 : any two prime nos share only one common divisor ,that is 1 sufficient
stat2 : every number has 1 as common divisor, since the statement says, one common divisor, GCD is 1 sufficient
IMO D Your stat 1 is incorrect. If you take x and y are 2 and 3 respectively...then GCD is 1 if x and y are both 3 and 3...then GCD is 3.... It is not mentioned that x and y are not equal... Hope this clears.. Aah you are absolutely correct. Answer will be B then Sent from my iPhone using GMAT Club Forum mobile app



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Re: If x and y are both positive integers, what is their greatest common
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19 Jan 2017, 13:40
mohit_w wrote: Even I thought the answer is D.
But, the only reason I can think of D not being the correct answer choice, is no where in the question it being mentioned that they are "Distinct" +ve integers.
Any one who can clarify? You are correct mohit_w. Unless its not mentioned , we cannot assume .
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Re: If x and y are both positive integers, what is their greatest common
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25 Apr 2017, 15:37
msk0657 wrote: mohshu wrote: Stat 1 : any two prime nos share only one common divisor ,that is 1 sufficient
stat2 : every number has 1 as common divisor, since the statement says, one common divisor, GCD is 1 sufficient
IMO D Your stat 1 is incorrect. If you take x and y are 2 and 3 respectively...then GCD is 1 if x and y are both 3 and 3...then GCD is 3.... It is not mentioned that x and y are not equal... Hope this clears.. good example of why you shouldn't make additional assumptions when you are not required to!!! I definitely fell for D, but now I see why B is the correct answer! We were NEVER told that x and y are distinct integers!



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Re: If x and y are both positive integers, what is their greatest common
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01 Oct 2019, 12:52
Bunuel wrote: If x and y are both positive integers, what is their greatest common factor?
(1) x and y are prime numbers.
(2) x and y share only one common divisor. Option 1 is insufficient since: If x=2 and y=2 than GCF=2=x=y If X=2 and y=3 than GCF=1 Option 2 This statement tells us that GCF=1 Hence sufficient




Re: If x and y are both positive integers, what is their greatest common
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01 Oct 2019, 12:52






