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

It is currently 23 Jul 2014, 02:03

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

Silly doubt about Modulus questions

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 07 Nov 2009
Posts: 313
Followers: 3

Kudos [?]: 53 [0], given: 20

Silly doubt about Modulus questions [#permalink] New post 01 Feb 2012, 04:13
1
This post was
BOOKMARKED
Silly doubt :oops:

When we solve the below equation , how many possible solutions we have?
|x – 3| = |2x – 3|

Which of the below cases we need to consider when we face such a equation?
Case 1
+LHS = +RHS
Case 2
-LHS = -LHS
Case 3
-LHS = +RHS
Case 4
LHS = -RHS
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18693
Followers: 3232

Kudos [?]: 22236 [0], given: 2601

Re: Silly doubt about Modulus questions [#permalink] New post 01 Feb 2012, 04:20
Expert's post
rohitgoel15 wrote:
Silly doubt :oops:

When we solve the below equation , how many possible solutions we have?
|x – 3| = |2x – 3|

Which of the below cases we need to consider when we face such a equation?
Case 1
+LHS = +RHS
Case 2
-LHS = -LHS
Case 3
-LHS = +RHS
Case 4
LHS = -RHS


|x – 3| = |2x – 3| can take only two forms: when they expand with the same sign (notice that ++ and -- will give you the same exact expression) and when they expand with the different signs (notice that +- and -+ will give you the same exact expression).

Case 1: x-3=2x-3 --> x=0;
Case 1: x-3=-(2x-3) --> x=2.

Check Tough and Tricky Absolute values and Inequalities Questions with detailed solutions: inequality-and-absolute-value-questions-from-my-collection-86939.html

Hope it 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

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Expert Post
1 KUDOS received
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 4566
Location: Pune, India
Followers: 1029

Kudos [?]: 4454 [1] , given: 162

Re: Silly doubt about Modulus questions [#permalink] New post 02 Feb 2012, 00:39
1
This post received
KUDOS
Expert's post
rohitgoel15 wrote:
Silly doubt :oops:

When we solve the below equation , how many possible solutions we have?
|x – 3| = |2x – 3|

Which of the below cases we need to consider when we face such a equation?
Case 1
+LHS = +RHS
Case 2
-LHS = -LHS
Case 3
-LHS = +RHS
Case 4
LHS = -RHS


Or you can forget all cases and do it logically!
|x – 3| means distance from point 3 on the number line.
|2x – 3| = 2|x – 3/2| means twice of distance from 1.5 on number line.

Where will these distances be equal?

It will be at a third of the distance between 1.5 and 3 and also at 1.5 to the left of 1.5 as shown in the two diagrams below:
Attachment:
Ques3.jpg
Ques3.jpg [ 6.93 KiB | Viewed 840 times ]


i.e. x can take two values 2 and 0.

For more on the theory of mods, check:
http://www.veritasprep.com/blog/2011/01 ... edore-did/
http://www.veritasprep.com/blog/2011/01 ... s-part-ii/

_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Save $100 on Veritas Prep GMAT Courses And Admissions Consulting
Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.

Veritas Prep Reviews

Senior Manager
Senior Manager
avatar
Joined: 07 Nov 2009
Posts: 313
Followers: 3

Kudos [?]: 53 [0], given: 20

Re: Silly doubt about Modulus questions [#permalink] New post 05 Feb 2012, 20:33
Thanks Karishma and Bunuel. Kudos to both !
Re: Silly doubt about Modulus questions   [#permalink] 05 Feb 2012, 20:33
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic DOUBT ABOUT DIFFICULTY OF QUESTIONS. spla626 1 06 Nov 2013, 09:51
Experts publish their posts in the topic Question on modulus? fozzzy 3 21 May 2013, 21:42
1 Experts publish their posts in the topic Doubt about 'Question of the day' series. thesilverlining 3 12 Feb 2013, 10:45
2 Silly but important question about eyeglasses workingonit121 2 12 Mar 2012, 05:57
A silly question fastidious 1 27 Apr 2006, 09:46
Display posts from previous: Sort by

Silly doubt about Modulus questions

  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®.