BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Please clarify Official Guide DS Prob 1

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Senior | Next Rank: 100 Posts
Posts: 53
Joined: Thu Dec 25, 2014 2:23 pm
Thanked: 1 times
by utkalnayak » Sun Jan 04, 2015 5:00 pm
"What is the value of |X| ?

(1) X = - |X|
(2) X^2 = 4

The explanation says with option 1, it can be derived that the value of |X| is positive or 0. I did not understand how it can be any positive number. I think it should be always 0. Can anybody explain ? TIA
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Sun Jan 04, 2015 5:22 pm
utkalnayak wrote:What is the value of |x| ?

(1) x = -|x|
(2) x² = 4
Target question: What is the value of |x|?

NOTE: the question is not asking for the value of x. We want the value of |x|

Statement 1: x = -|x|
There are several values of x that satisfy this condition. Here are two:
Case a: x = 0, since 0 = -|0|. In this case |x| = |0| = 0
Case b: x = -1, since -1 = -|-1|. In this case |x| = |-1| = 1
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: x² = 4
This means that x = 2 OR x = -2
Don't make the mistake of concluding that statement 2 is not sufficient. We are not asked to find the value of x. We want the value of |x|
If x = 2, then |x| = |2| = 2
If x = -2, then |x| = |-2| = 2
In both cases, we get the same answer to the target question: |x| = 2
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer = B

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
GMAT Instructor
Posts: 2630
Joined: Wed Sep 12, 2012 3:32 pmFollowed by: 119 members
Location: East Bay all the way
Thanked: 625 times
GMAT Score:780

by Matt@VeritasPrep » Mon Jan 05, 2015 11:16 am
As an addendum to this, x = -|x| is just a confusing way of saying that x ≤ 0. (The GMAT is quite fond of this equation, as it says something simple in the most painful way imaginable. :D)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1