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G, M, and N are integers, M=X+6; G is the greatest common [#permalink]
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06 May 2006, 03:43
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G, M, and N are integers, M=X+6; G is the greatest common factor of M and N. G=?
1) N=2531
2) N=X+7



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Joined: 13 Nov 2003
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From A) 2531 is a prime so M=q* 2531. Since 2531 is the GREATEST common factor, or G, then G2531 so A SUF
From B) seems that M and N are consecutive integers and their GCF is 1 so B is SUFF
Tough Q



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Joined: 18 Jan 2006
Posts: 27

It is C.
1 Not suff  We donot know what is X. X can be 2525 in which case G will be 2531 or X can be other than 2525 in which case G will be 1.
2 Not suff  We donot know what is M and N.
Combine together. we have M = X + 6 and N = X + 7. 2 consecutive numbers and hence G is 1.



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Joined: 29 Apr 2003
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narsi wrote: It is C.
1 Not suff  We donot know what is X. X can be 2525 in which case G will be 2531 or X can be other than 2525 in which case G will be 1.
2 Not suff  We donot know what is M and N.
Combine together. we have M = X + 6 and N = X + 7. 2 consecutive numbers and hence G is 1.
Why do u think B is not sufficient? I think B is! It shows that they are consecutive, hence relatively prime!



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Joined: 27 Mar 2006
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BG wrote: From A) 2531 is a prime so M=q* 2531. Since 2531 is the GREATEST common factor, or G, then G2531 so A SUF
How do you quickly determine if a number is prime?



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Joined: 11 Oct 2005
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trick question. I agree with B



VP
Joined: 29 Dec 2005
Posts: 1341

BG wrote: From A) 2531 is a prime so M=q* 2531. Since 2531 is the GREATEST common factor, or G, then G2531 so A SUF From B) seems that M and N are consecutive integers and their GCF is 1 so B is SUFF Tough Q
beautiful work. but how do you know that, in a, gcf is 2531? m could also be 2531. so gcf could be 1 or 2531.
agree with B.



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Joined: 10 May 2006
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shevy wrote: BG wrote: From A) 2531 is a prime so M=q* 2531. Since 2531 is the GREATEST common factor, or G, then G2531 so A SUF
How do you quickly determine if a number is prime?
Does anyone have any answer to this? I wouldn't be able to tell just by looking at the problem that 2531 is a prime number. Any shortcuts to calculate this?
Thanks!



Senior Manager
Joined: 08 Jun 2004
Posts: 495
Location: Europe

Definitely 'B'.
M=X+6; from 2) N=X+7.
M=N1, so we have 1 as GCF.
Guys please remember me the rule when the digit is divided by 3, when by 4, by 6, by 7, by 8, by 9.
I forgot it. Just remember something like when the sum of the last 2 digits of any number is divided by 4 the number is divided by 4.
Thank you.










