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

It is currently 25 May 2015, 10:25

Today:

Free Access to GMAT Club Tests - May 25th for Memorial Day!!


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

Set M contains numbers that satisfy the condition that, if

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 24 Jul 2012
Posts: 13
Schools: Schulich '16
GMAT 1: 610 Q49 V26
WE: Consulting (Consulting)
Followers: 0

Kudos [?]: 10 [0], given: 7

Set M contains numbers that satisfy the condition that, if [#permalink] New post 17 Sep 2012, 04:54
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

45% (01:35) correct 55% (00:47) wrong based on 110 sessions
Set M contains numbers that satisfy the condition that, if integer x is in the set then x+3 will also be in the set M. If -4 is one of the value in the set, which of the following numbers must also be present in the set M.

I. -7
II. -1
III. 2

A. I only
B. II only
C. I and II only
D. II and III only
E. I, II and III
[Reveal] Spoiler: OA

Last edited by Bunuel on 17 Sep 2012, 05:50, edited 1 time in total.
Edited the question.
Manager
Manager
User avatar
Status: Fighting hard
Joined: 04 Jul 2011
Posts: 72
GMAT Date: 10-01-2012
Followers: 2

Kudos [?]: 33 [0], given: 84

Re: Set M contains numbers that satisfy the condition that, if [#permalink] New post 17 Sep 2012, 05:09
If -4 is part of the list, then -4+3(i.e -1) & -1+3(i.e 2) "MUST" be part of the set. Whereas -4-3(i.e -7) "COULD" be a part of the list
Hence D is the answer.
_________________

I will rather do nothing than be busy doing nothing - Zen saying

Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 27493
Followers: 4312

Kudos [?]: 42288 [1] , given: 6012

Re: Set M contains numbers that satisfy the condition that, if [#permalink] New post 17 Sep 2012, 05:53
1
This post received
KUDOS
Expert's post
Vamshi8411 wrote:
Set M contains numbers that satisfy the condition that, if integer x is in the set then x+3 will also be in the set M. If -4 is one of the value in the set, which of the following numbers must also be present in the set M.

I. -7
II. -1
III. 2

A. I only
B. II only
C. I and II only
D. II and III only
E. I, II and III


Notice that we are asked "which of the following numbers MUST also be present in the set M" not "COULD be in the set".

Now, if -4 is in the set, then -4+3=-1 must be in the set. Since -1 is in the set then -1+3=2 must be in the set. Could -7 be in the set? Certainly, but we don't know that for sure.

Answer: D.

Hope it's clear.
_________________

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

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
User avatar
Joined: 11 Nov 2011
Posts: 53
Location: United States
Concentration: Finance, Human Resources
GPA: 3.33
WE: Consulting (Non-Profit and Government)
Followers: 0

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

GMAT ToolKit User
Re: Set M contains numbers that satisfy the condition that, if [#permalink] New post 03 Dec 2014, 04:10
Pansi wrote:
If -4 is part of the list, then -4+3(i.e -1) & -1+3(i.e 2) "MUST" be part of the set. Whereas -4-3(i.e -7) "COULD" be a part of the list
Hence D is the answer.


why -7 could be in the list? Why not must? why can't we use the rule backward?

thanks
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 27493
Followers: 4312

Kudos [?]: 42288 [0], given: 6012

Re: Set M contains numbers that satisfy the condition that, if [#permalink] New post 03 Dec 2014, 05:56
Expert's post
evdo wrote:
Pansi wrote:
If -4 is part of the list, then -4+3(i.e -1) & -1+3(i.e 2) "MUST" be part of the set. Whereas -4-3(i.e -7) "COULD" be a part of the list
Hence D is the answer.


why -7 could be in the list? Why not must? why can't we use the rule backward?

thanks


If integer x is in the set then x+3 will also be in the set does NOT mean that the reverse must be true.

If integer x is in the set then x+3 will also be in the set does NOT mean that if integer x+3 is in the set then x must also be in the set.

Check similar questions to practice:
for-a-certain-set-of-numbers-if-x-is-in-the-set-then-both-161920.html
for-a-certain-set-of-numbers-if-x-is-in-the-set-then-x-136580.html
a-set-of-numbers-has-the-property-that-for-any-number-t-in-t-98829.html
if-p-is-a-set-of-integers-and-3-is-in-p-is-every-positive-96630.html
k-is-a-set-of-numbers-such-that-i-if-x-is-in-k-then-x-96907.html
k-is-a-set-of-integers-such-that-if-the-integer-r-is-in-k-103005.html
k-is-a-set-of-numbers-such-that-166908.html

Hope this helps.
_________________

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

GMAT Club Premium Membership - big benefits and savings

Re: Set M contains numbers that satisfy the condition that, if   [#permalink] 03 Dec 2014, 05:56
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic Set A contains 20 numbers and Set B contains 40 numbers. Is piyushksharma 1 10 May 2012, 05:17
4 Experts publish their posts in the topic Set M contains number that satisfy the condition that, if integer x is UtterNonsense 6 26 Jul 2011, 05:49
Set A contains all the even numbers..... pzazz12 2 08 Oct 2010, 04:39
How many 3-digit numbers satisfy the following conditions: vscid 1 05 Jan 2008, 13:17
How many 3-digit numbers satisfy the following conditions: jodeci 1 08 Apr 2006, 15:09
Display posts from previous: Sort by

Set M contains numbers that satisfy the condition that, if

  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®.