Find all School-related info fast with the new School-Specific MBA Forum

It is currently 01 Sep 2014, 20:50

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If x and y are positive integers such that x = 8y +12, what

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 23 May 2005
Posts: 266
Location: Sing/ HK
Followers: 1

Kudos [?]: 9 [0], given: 0

GMAT Tests User
If x and y are positive integers such that x = 8y +12, what [#permalink] New post 29 Nov 2006, 09:47
If x and y are positive integers such that x = 8y +12, what is the greatest common divisor of x and y?

(1) x =12u, where u is an integer

(2) x =12z, where z is an integer
_________________

Impossible is nothing

Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2006
Posts: 375
Followers: 1

Kudos [?]: 1 [0], given: 0

GMAT Tests User
Re: GMAT Prep: Greatest Common Divisor [#permalink] New post 29 Nov 2006, 11:49
Hermione wrote:
If x and y are positive integers such that x = 8y +12, what is the greatest common divisor of x and y?

(1) x =12u, where u is an integer

(2) x =12z, where z is an integer


Both statements essentially tell us the same thing?

From 1) 12u = 8y + 12 or u=2y/3 + 1 u=>3 to give integer values of y INSUFF

2) Same as for 1) INSUFF

Taking both together, x can equal 36 giving GCD of x&y as 3 or 60 giving GCD of 6. INSUFF

E for me
Director
Director
User avatar
Joined: 05 Feb 2006
Posts: 904
Followers: 1

Kudos [?]: 33 [0], given: 0

GMAT Tests User
 [#permalink] New post 29 Nov 2006, 12:01
E this one....

Both statements can yield x=12 y=3 or x=36, y=4....
Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2006
Posts: 375
Followers: 1

Kudos [?]: 1 [0], given: 0

GMAT Tests User
 [#permalink] New post 29 Nov 2006, 12:14
SimaQ wrote:
E this one....

Both statements can yield x=12 y=3 or x=36, y=4....


If x=12 then y cant be an integer. If x=36 then y=3
Director
Director
avatar
Joined: 01 Oct 2006
Posts: 500
Followers: 1

Kudos [?]: 16 [0], given: 0

GMAT Tests User
 [#permalink] New post 29 Nov 2006, 13:24
x=8y+12
st1 says x=12u thus 12(u-1)=8y the GCD will change depending upon values of u and y..insuff
st2 same 1 insuff

combining also insuff

Thus answer is E
Manager
Manager
User avatar
Joined: 25 Nov 2006
Posts: 60
Followers: 2

Kudos [?]: 2 [0], given: 0

 [#permalink] New post 29 Nov 2006, 14:03
from 1:we can conclude that the value of 'u' may be 3,5,7,9.........
since x,y given to be positive integers.
hence we cannot conclude or get the values of x and y from where we cannot get the gcd.
option E is the wright answer.
Director
Director
User avatar
Joined: 05 Feb 2006
Posts: 904
Followers: 1

Kudos [?]: 33 [0], given: 0

GMAT Tests User
 [#permalink] New post 30 Nov 2006, 00:03
MBAlad wrote:
SimaQ wrote:
E this one....

Both statements can yield x=12 y=3 or x=36, y=4....


If x=12 then y cant be an integer. If x=36 then y=3


Yes you are right.... :) was in a rush on this one... however the values do not really matter, the point is that there can be several values.... :)
Senior Manager
Senior Manager
avatar
Joined: 23 May 2005
Posts: 266
Location: Sing/ HK
Followers: 1

Kudos [?]: 9 [0], given: 0

GMAT Tests User
 [#permalink] New post 30 Nov 2006, 07:07
Oh sh*t! Don't kill me. The second statemt should read

(2) y=12z, where z is an integer

So sorry!!!
_________________

Impossible is nothing

SVP
SVP
User avatar
Joined: 05 Jul 2006
Posts: 1542
Followers: 5

Kudos [?]: 71 [0], given: 39

 [#permalink] New post 30 Nov 2006, 07:14
If x and y are positive integers such that x = 8y +12, what is the greatest common divisor of x and y?

(1) x =12u, where u is an integer

(2) y =12z, where z is an integer


from one

12(u-1) = 8y.ie: y = 3/2 ( u-1) .insuff

from two

y is a multiple of 12 , from given x = 12*8*y+12 ie a multiple of 12 = 12(8y+1)

thus the greatest common divisor is 12...B is my answer
Manager
Manager
avatar
Joined: 17 Dec 2004
Posts: 73
Followers: 2

Kudos [?]: 3 [0], given: 0

 [#permalink] New post 30 Nov 2006, 09:18
I get B.

The stem tells us that x = 8y + 12.

S1: x = 12u, where u is an integer. This tells us that: 12u = 8y + 12 ---> 3u = 2y + 3 ---> 3(u-1) = 2y ---> u = (2y)/3 + 1. Because this can give multiple values for x ---> INSUFF.

S2: y = 12z, where z is an integer. This tells us that: x = 8(12z) + 12 ---> x = 12(8z +1). From this it follows that, for all values of z (and thus y), the greatest common factor is 12 ---> SUFF.

Therefore B.

What is the OA?
Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2006
Posts: 375
Followers: 1

Kudos [?]: 1 [0], given: 0

GMAT Tests User
 [#permalink] New post 30 Nov 2006, 14:37
I'm going with B now :wink:

x = 8(12z) + 12 ---> x = 96z + 12

GCD = 12

Statement 1) Still INSUFF
2) Now SUFF
Manager
Manager
avatar
Joined: 01 Feb 2006
Posts: 83
Location: New York
Followers: 1

Kudos [?]: 0 [0], given: 0

 [#permalink] New post 01 Dec 2006, 06:43
OA is B. you guys got it !!
  [#permalink] 01 Dec 2006, 06:43
    Similar topics Author Replies Last post
Similar
Topics:
If x and y are positive integers such that x = 8y + 12, what 700dreamer 1 07 Jun 2007, 18:53
If x and y are positive integers such that x=8y+12, what is tl372 3 21 May 2006, 09:58
If x and y are positive integers such that x=8y+12, what is Vithal 6 05 Jun 2005, 17:43
IF x and y are positive integes such that x=8y+12, what is ruhi 2 10 Nov 2004, 11:49
If x and y are positive integers such that x=8y+12, what is GMATPIPO 7 21 Oct 2004, 18:28
Display posts from previous: Sort by

If x and y are positive integers such that x = 8y +12, what

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.