What is the greatest common factor of positive integers x : DS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 17 Jan 2017, 10:50

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# What is the greatest common factor of positive integers x

Author Message
Director
Joined: 01 May 2007
Posts: 792
Followers: 1

Kudos [?]: 287 [0], given: 0

What is the greatest common factor of positive integers x [#permalink]

### Show Tags

15 Mar 2008, 12:26
00:00

Difficulty:

(N/A)

Question Stats:

75% (01:16) correct 25% (00:00) wrong based on 28 sessions

### HideShow timer Statistics

What is the greatest common factor of positive integers x and y?

1) The GCF of x/2 and y/2 is 5?
2) x and y are even.
Senior Manager
Joined: 06 Jul 2006
Posts: 295
Location: SFO Bay Area
Schools: Berkeley Haas
Followers: 2

Kudos [?]: 61 [0], given: 0

Re: PS: Greatest Common Factor [#permalink]

### Show Tags

15 Mar 2008, 14:20
jimmyjamesdonkey wrote:
What is the greatest common factor of positive integers x and y?

1) The GCF of x/2 and y/2 is 5?
2) x and y are even.

A shd be it.

St1: If the GCF is 5, then with X and Y, the GCF will be 10...Suff.

St2: Even: X = 10, Y = 20, GCF = 10.
X = 18, Y = 24, GCF = 6.
Not suff.

Whats OA ?
Manager
Joined: 15 Mar 2008
Posts: 51
Followers: 1

Kudos [?]: 26 [0], given: 0

Re: PS: Greatest Common Factor [#permalink]

### Show Tags

15 Mar 2008, 14:44
If x/2 and y/2 have the GCF of 5, it means that x/2 and y/2 should both be divisible by 5. This implies that x and y should both be divisible by 10. As an example you can take 10 and 20 or 20 and 30 or 30 and 40 and so on. If you take alternate 10s like 20 and 40, then 10 and 20 do not have the GCF of 5 but have the GCF of 10. That contradicts our first condition.
rkassal
Manager
Joined: 16 May 2011
Posts: 204
Concentration: Finance, Real Estate
GMAT Date: 12-27-2011
WE: Law (Law)
Followers: 1

Kudos [?]: 76 [0], given: 37

Re: PS: Greatest Common Factor [#permalink]

### Show Tags

24 May 2011, 04:00
FOR ME:

X/2=5*A X=2*5*A
Y/2=5*B Y=2*5*B HENCE :2 AND 5ARE THE GCF
Current Student
Joined: 26 May 2005
Posts: 565
Followers: 18

Kudos [?]: 203 [0], given: 13

Re: PS: Greatest Common Factor [#permalink]

### Show Tags

24 May 2011, 04:13
Clean A .

X/2 and Y/2 has 5 as GCF , which mean x, y will have 10 GCF,
Manager
Joined: 03 Jun 2010
Posts: 138
Location: Dubai, UAE
Schools: IE Business School, Manchester Business School, HEC Paris, Rotterdam School of Management, Babson College
Followers: 2

Kudos [?]: 4 [0], given: 4

Re: PS: Greatest Common Factor [#permalink]

### Show Tags

24 May 2011, 04:43
ok so i agree statement 2 is insufficient, however i do have a quick question regarding statement 1, you have said if x/2 and y/2 have a GCF of 5, then the GCF of x and y is 10. However i didnt really apply the straight forward technique so need your help here, please find below my technique

assuming
x= 20
y=10

x/2= 10
y/2= 5

10= 2*5
5= 5*1

Hence GCF would be the common numbers with the lowest exponent, i.e. 5^1=5.
VP
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 1353
Followers: 17

Kudos [?]: 240 [0], given: 10

Re: PS: Greatest Common Factor [#permalink]

### Show Tags

25 May 2011, 22:46
its a 10 using A here.
_________________

Visit -- http://www.sustainable-sphere.com/
Promote Green Business,Sustainable Living and Green Earth !!

Re: PS: Greatest Common Factor   [#permalink] 25 May 2011, 22:46
Display posts from previous: Sort by