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

It is currently 24 Oct 2014, 00:00

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

What is the greatest common divisor of positive integers m

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Senior Manager
Senior Manager
User avatar
Joined: 16 Jan 2009
Posts: 362
Concentration: Technology, Marketing
GMAT 1: 700 Q50 V34
GPA: 3
WE: Sales (Telecommunications)
Followers: 2

Kudos [?]: 73 [1] , given: 16

What is the greatest common divisor of positive integers m [#permalink] New post 07 Jun 2009, 10:12
1
This post received
KUDOS
5
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

60% (01:35) correct 40% (00:44) wrong based on 235 sessions
What is the greatest common divisor of positive integers m and n.

(1) m is a prime number
(2) 2n=7m
[Reveal] Spoiler: OA

_________________

Lahoosaher


Last edited by Bunuel on 28 Dec 2013, 02:51, edited 2 times in total.
Edited the question and added the OA
Director
Director
avatar
Joined: 23 May 2008
Posts: 840
Followers: 3

Kudos [?]: 31 [0], given: 0

Re: DS : GCD [#permalink] New post 07 Jun 2009, 17:29
amolsk11 wrote:
what is the greatest common divisor of the positive integers m and n.
1)m is prime
2)2n=7m
[Reveal] Spoiler:
C



m&n GCF?

1) m is prime

no info on n, insuff

2) 2n=7m; n=7/2 m or 1:3.5 ratio

n could be 2, m could be 7, GCF=1
n could be 8, m could be 28, GCF=4
nsuff

together
m has to be 7 for n to be an integer, GCF=1
Manager
Manager
avatar
Joined: 11 Aug 2008
Posts: 162
Followers: 1

Kudos [?]: 36 [0], given: 8

Re: DS : GCD [#permalink] New post 08 Jun 2009, 18:14
1) no info about n (insuf)
2) n=7m/2. To make n an integer, m=2b (b is an pos integer). With b=1,2,3...we have varied GCD of m and n
(insuf)
Together we have m=2, n=7 GCD=1, suf
Intern
Intern
avatar
Joined: 16 May 2011
Posts: 6
Followers: 0

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

Re: DS : GCD [#permalink] New post 04 Jul 2011, 02:50
option 2 gives 2n=7m. Therefore n=7m/2
HCF of m and 7m/2 is always m/2. So answer should be optin 2 right. what do you think guys
Manager
Manager
User avatar
Joined: 29 Jun 2011
Posts: 165
WE 1: Information Technology(Retail)
Followers: 3

Kudos [?]: 13 [0], given: 29

Re: what is the greatest common divisor of the positive integers [#permalink] New post 02 Mar 2012, 10:48
OA is C.

1)m is prime
Clearly insufficient.

2)2n=7m
can be written as n= 7m/2. n & m are integers.
Put m=1,2,3,4 .... therefore m has to be a multiple of 2.
Insufficient.

Combined-
m is prime(stat1) and m= multiple of 2(stat2)

Hence m=2 & n=7

GCF is 1.
Expert Post
6 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23398
Followers: 3611

Kudos [?]: 28863 [6] , given: 2854

Re: What is the greatest common divisor of the positive integers [#permalink] New post 02 Mar 2012, 11:20
6
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
What is the greatest common divisor of positive integers m and n?

(1) m is a prime number --> if m=2=prime and n=1 then GCD(m,n)=1 but if m=2=prime and n=4 then GCD(m,n)=2. Two different answers, hence not sufficient.

(2) 2n=7m --> \frac{m}{n}=\frac{2}{7} --> m is a multiple of 2 and n is a multiple of 7, but this is still not sufficient: if m=2 and n=7 then GCD(m,n)=1 (as both are primes) but if m=4 and n=14 then GCD(m,n)=2 (basically as \frac{m}{n}=\frac{2x}{7x} then as 2 and 7 are primes then GCD(m, n)=x). Two different answers, hence not sufficient.

(1)+(2) Since from (1) m=prime and from (2) \frac{m}{n}=\frac{2}{7} then m=2=prime and n=7, hence GCD(m,n)=1. Sufficient.

Answer: C.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 05 Jun 2012
Posts: 1
Followers: 0

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

Re: What is the greatest common divisor of positive integers m [#permalink] New post 24 Sep 2012, 21:02
1) This statement says that M is Prime no, So N can be Prime/Composite. If N is Prime , clearly GCD will be 1, If N is composite also GCD will be 1( Except when M itself is a divisor of N, means N<>kM(not equals)), If N=kM then GCD(M,N) will be M it self.(where k is an integer)

2)2N=7M, its clearly not sufficient.

Combining:

From the statement 1, if we can get N=kM or not(where k is an integer) then we will be sure whats the GCD. As from the statement 2, we can see that N=7/2 M, and 7/2 is not an integer. So clearly GCD will be 1.


So answer is C.

---If it is stupid but it works, it isn't stupid.
Director
Director
avatar
Joined: 17 Apr 2013
Posts: 550
Concentration: Entrepreneurship, Leadership
Schools: HBS '16
GMAT Date: 11-30-2013
GPA: 3.3
Followers: 3

Kudos [?]: 65 [0], given: 250

CAT Tests
Re: What is the greatest common divisor of the positive integers [#permalink] New post 24 Sep 2013, 10:07
Bunuel wrote:
What is the greatest common divisor of positive integers m and n?

(1) m is a prime number --> if m=2=prime and n=1 then GCD(m,n)=1 but if m=2=prime and n=4 then GCD(m,n)=2. Two different answers, hence not sufficient.

(2) 2n=7m --> \frac{m}{n}=\frac{2}{7} --> m is a multiple of 2 and n is a multiple of 7, but this is still not sufficient: if m=2 and n=7 then GCD(m,n)=1 (as both are primes) but if m=4 and n=14 then GCD(m,n)=2 (basically as \frac{m}{n}=\frac{2x}{7x} then as 2 and 7 are primes then GCD(m, n)=x). Two different answers, hence not sufficient.

(1)+(2) Since from (1) m=prime and from (2) \frac{m}{n}=\frac{2}{7} then m=2=prime and n=7, hence GCD(m,n)=1. Sufficient.

Answer: C.


Greatest Common divisor and Highest common factor are same thing Bunuel?

Because n= 7m/2 (Taking both this is true only for m = 2) So Greatest common divisor is 2 not 1, Isn't it?
_________________

Like my post Send me a Kudos :) It is a Good manner.

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23398
Followers: 3611

Kudos [?]: 28863 [0], given: 2854

Re: What is the greatest common divisor of the positive integers [#permalink] New post 24 Sep 2013, 14:12
Expert's post
honchos wrote:
Bunuel wrote:
What is the greatest common divisor of positive integers m and n?

(1) m is a prime number --> if m=2=prime and n=1 then GCD(m,n)=1 but if m=2=prime and n=4 then GCD(m,n)=2. Two different answers, hence not sufficient.

(2) 2n=7m --> \frac{m}{n}=\frac{2}{7} --> m is a multiple of 2 and n is a multiple of 7, but this is still not sufficient: if m=2 and n=7 then GCD(m,n)=1 (as both are primes) but if m=4 and n=14 then GCD(m,n)=2 (basically as \frac{m}{n}=\frac{2x}{7x} then as 2 and 7 are primes then GCD(m, n)=x). Two different answers, hence not sufficient.

(1)+(2) Since from (1) m=prime and from (2) \frac{m}{n}=\frac{2}{7} then m=2=prime and n=7, hence GCD(m,n)=1. Sufficient.

Answer: C.


Greatest Common divisor and Highest common factor are same thing Bunuel?

Because n= 7m/2 (Taking both this is true only for m = 2) So Greatest common divisor is 2 not 1, Isn't it?


Yes, GCD and GCF are the same thing.

But couldn't understand your second point: the greatest common divisor of 2 and 7 is 1. How can it be 2? Is 7 divisible by 2?
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Director
Director
avatar
Joined: 17 Apr 2013
Posts: 550
Concentration: Entrepreneurship, Leadership
Schools: HBS '16
GMAT Date: 11-30-2013
GPA: 3.3
Followers: 3

Kudos [?]: 65 [0], given: 250

CAT Tests
Re: What is the greatest common divisor of the positive integers [#permalink] New post 24 Sep 2013, 22:12
Bunuel,
Our m is coming as 2, so isn't 2 a GCD, Or may be I have misunderstood the solution?
_________________

Like my post Send me a Kudos :) It is a Good manner.

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23398
Followers: 3611

Kudos [?]: 28863 [0], given: 2854

Re: What is the greatest common divisor of the positive integers [#permalink] New post 24 Sep 2013, 23:54
Expert's post
honchos wrote:
Bunuel,
Our m is coming as 2, so isn't 2 a GCD, Or may be I have misunderstood the solution?


The question asks: what is the greatest common divisor of positive integers m and n?

We got that m=2 and n=7. What is the greatest common divisor of 2 and 7? Is it 2? No, it's 1.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Director
Director
avatar
Joined: 17 Apr 2013
Posts: 550
Concentration: Entrepreneurship, Leadership
Schools: HBS '16
GMAT Date: 11-30-2013
GPA: 3.3
Followers: 3

Kudos [?]: 65 [0], given: 250

CAT Tests
Re: What is the greatest common divisor of the positive integers [#permalink] New post 25 Sep 2013, 00:26
Bunuel wrote:
honchos wrote:
Bunuel,
Our m is coming as 2, so isn't 2 a GCD, Or may be I have misunderstood the solution?


The question asks: what is the greatest common divisor of positive integers m and n?

We got that m=2 and n=7. What is the greatest common divisor of 2 and 7? Is it 2? No, it's 1.



Got it, may be I am getting panic as my exam is coming closer, so could not see even clear things.
_________________

Like my post Send me a Kudos :) It is a Good manner.

Re: What is the greatest common divisor of the positive integers   [#permalink] 25 Sep 2013, 00:26
    Similar topics Author Replies Last post
Similar
Topics:
what is the greatest common divisor of positive integers m young_gun 4 06 Nov 2007, 12:49
What is the greatest common divisor of positive integers m dancer 9 25 Oct 2006, 18:29
What is the greatest common divisor of positive integers m mrmikec 4 16 Jun 2006, 21:39
What is the greatest common divisor of positive integers m gmat_crack 5 08 Apr 2006, 20:36
What is the greatest common divisor of positive integers m twixt 4 22 Nov 2004, 06:50
Display posts from previous: Sort by

What is the greatest common divisor of positive integers m

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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®.