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

It is currently 22 Nov 2014, 15:58

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 mn = 3(m + 1) + n and m and n are integers

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
2 KUDOS received
Booth Thread Master
User avatar
Joined: 06 Sep 2013
Posts: 1942
Concentration: Finance
GMAT 1: 710 Q48 V39
GPA: 3.5
Followers: 20

Kudos [?]: 231 [2] , given: 343

GMAT ToolKit User
If mn = 3(m + 1) + n and m and n are integers [#permalink] New post 20 Sep 2013, 15:05
2
This post received
KUDOS
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

54% (02:10) correct 46% (01:24) wrong based on 112 sessions
If mn = 3(m + 1) + n and m and n are integers, m could be any of the following values EXCEPT:

(A) 2
(B) 3
(C) 4
(D) 5
(E) 7
[Reveal] Spoiler: OA
Expert Post
2 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 24007
Followers: 3726

Kudos [?]: 31040 [2] , given: 3268

Re: If mn = 3(m + 1) + n and m and n are integers [#permalink] New post 20 Sep 2013, 15:09
2
This post received
KUDOS
Expert's post
jlgdr wrote:
If mn = 3(m + 1) + n and m and n are integers, m could be any of the following values EXCEPT:

(A) 2
(B) 3
(C) 4
(D) 5
(E) 7


mn = 3(m + 1) + n
mn - n = 3(m + 1)
n = 3(m + 1)/(m-1)

n won't be an integer only if m = 5 (from the options).

Answer: D.
_________________

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

Take a Survey about GMAT Prep - Win Prizes!

Intern
Intern
avatar
Joined: 04 Dec 2012
Posts: 8
Schools: ISB '15
Followers: 1

Kudos [?]: 0 [0], given: 7

Re: If mn = 3(m + 1) + n and m and n are integers [#permalink] New post 22 Sep 2013, 04:00
jlgdr wrote:
If mn = 3(m + 1) + n and m and n are integers, m could be any of the following values EXCEPT:

(A) 2
(B) 3
(C) 4
(D) 5
(E) 7


Alternative way of looking at it

mn = 3(m+1) + n
n = 3(m+1)/(m-1)
n = 3[(m-1)+2)]/(m-1)
n = 3(1 + 2/(m-1))
n = 3 + 6/(m-1)

=> given answer choice - 1 should divide 6.

Only 5 does not satisfy the above condition.
Senior Manager
Senior Manager
User avatar
Joined: 03 Dec 2012
Posts: 367
Followers: 0

Kudos [?]: 43 [0], given: 291

Re: If mn = 3(m + 1) + n and m and n are integers [#permalink] New post 15 Oct 2013, 06:24
This is how I solved the question mn=3(m+1)+n => mn= 3m+3 +n => mn-3m=n+3 => m(n-3)=n+3 => m=n+3/n-3 In this cast 7 fits the bill. Where am I going wrong Bunuel?
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 24007
Followers: 3726

Kudos [?]: 31040 [1] , given: 3268

Re: If mn = 3(m + 1) + n and m and n are integers [#permalink] New post 15 Oct 2013, 07:52
1
This post received
KUDOS
Expert's post
mohnish104 wrote:
This is how I solved the question mn=3(m+1)+n => mn= 3m+3 +n => mn-3m=n+3 => m(n-3)=n+3 => m=n+3/n-3 In this cast 7 fits the bill. Where am I going wrong Bunuel?


If m=7, then 7=(n+3)/(n-3) --> n=4=integer. Thus m could be 7.
_________________

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

Take a Survey about GMAT Prep - Win Prizes!

VP
VP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1285
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 10

Kudos [?]: 445 [0], given: 177

Re: If mn = 3(m + 1) + n and m and n are integers [#permalink] New post 23 Feb 2014, 21:37
mn = 3(m + 1) + n and m and n are integers-

Solved by placing the values directly from the options:

For m=2, 2n = 9 + n .......... OK
For m=3, 3n = 12 +n..........OK
For m=4, 4n = 15 + n..........OK
For m=5, 5n = 18 + n.......... 4n = 18... then n becomes a non-integer
So Answer = D = 5
_________________

Kindly press "+1 Kudos" to appreciate :)

Manager
Manager
User avatar
Affiliations: CrackVerbal
Joined: 03 Oct 2013
Posts: 181
Location: India
GMAT 1: 780 Q51 V46
Followers: 22

Kudos [?]: 92 [0], given: 2

Re: If mn = 3(m + 1) + n and m and n are integers [#permalink] New post 23 Feb 2014, 22:13
jlgdr wrote:
If mn = 3(m + 1) + n and m and n are integers, m could be any of the following values EXCEPT:

(A) 2
(B) 3
(C) 4
(D) 5
(E) 7


Let us plug in:

m = 2 , 2(n) = 3(2 + 1) + n then n will be 9
m = 3, 3(n) = 3(4) + n, then n will be an integer
m = 4, 4(n) = 3(5) + n, then n will be an integer
m = 5, 5(n) = 3(6) + n, then n will be 18/4 (not an integer) (BINGO!)
m = 7, 7(n) = 3(8) + n, still n will be an integer

Answer is D.
_________________

If you find our response valuable, please encourage us with Kudos!

Live online classes by 99th percentile instructors!
http://gmat.crackverbal.com/gmat-courses/online/gmat-live-course/

Join the Verbal 40 Club & learn to Tackle Brutal GMAT Verbal Questions!
http://gmat.crackverbal.com/gmat-verbal-40-bangalore

Re: If mn = 3(m + 1) + n and m and n are integers   [#permalink] 23 Feb 2014, 22:13
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic If 3^m3^m3^m = 9^n, then m/n = Bunuel 3 04 Nov 2014, 09:21
2 Experts publish their posts in the topic If m and n are positive integers, is 3√m < √(m+n) ? irda 3 15 Aug 2013, 04:03
If m and n are positive integers and mn=k is m + n = k +1? marcodonzelli 2 07 Mar 2008, 11:44
If m and n are non zero integers, is m^n an integer? S1. freetheking 2 06 Aug 2006, 11:23
m and n are integers. Is m^n an integer? 1) n^m is positive gamjatang 5 11 Nov 2005, 08:09
Display posts from previous: Sort by

If mn = 3(m + 1) + n and m and n are integers

  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®.