• Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • examPAL
    Most awarded test prep in the world
    Now free for 30 days

    Available with Beat the GMAT members only code

    MORE DETAILS
    examPAL
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors

Is b < 0?

This topic has 2 expert replies and 0 member replies
james Junior | Next Rank: 30 Posts Default Avatar
Joined
05 Oct 2014
Posted:
17 messages

Is b < 0?

Post Wed Oct 08, 2014 9:32 pm
is b<0?

(i) b is a multiple of 13
(ii) b^3 < 13

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post Fri Oct 10, 2014 5:04 am
james wrote:
Is b < 0?

(i) b is a multiple of 13
(ii) b³ < 13
Target question: Is b negative?

Statement 1: b is a multiple of 13
Here are some multiples of 13: ....-39, -26, -13, 0, 13, 26, 39,...
As you can seem there are several values of b that satisfy the given condition. Let's examine two of them that yield CONFLICTING answers to the target question:
Case a: b = -13, in which case b IS negative
Case b: b = 0, in which case b is NOT negative
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: b³ < 13
There are several values of b that satisfy this condition. Here are two:
Case a: b = -1, in which case b IS negative
Case b: b = 0, in which case b is NOT negative
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
There are still several values of b that satisfy BOTH conditions. Here are two:
Case a: b = -13, in which case b IS negative
Case b: b = 0, in which case b is NOT negative
KEY TAKEAWAY: 0 is a multiple of all integers
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with Beat The GMAT's free 60-Day Study Guide

Check out the online reviews of our course
Come see all of our free resources

  • +1 Upvote Post
  • Quote
  • Flag
GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!

GMAT/MBA Expert

Post Wed Oct 08, 2014 9:46 pm
Hi james,

This question is perfect for TESTing Values:

We're asked if B < 0. This is a YES/NO question.

Fact 1: B is a multiple of 13.

By definition, a multiple can be positive, negative or 0.

So B could be….
13(1) = 13 Positive results gives us a NO answer
13(2) = 26
etc.

13(0) = 0 "Null" result gives us a NO answer

13(-1) = -13 Negative results give us a YES answer
13(-2) = -26
etc.
Fact 1 is INSUFFICIENT.

Fact 2: B^3 < 13

Here we have no restrictions on "multiples", so any number that fits this restriction will do…

If….
B = 1, then the answer is NO
B = -1, then the answer is YES
Fact 2 is INSUFFICIENT

Combined, we know…
B is a multiple of 13
B^3 < 13

If B = 0, then the answer to the question is NO
If B = -13, then the answer to the question is YES
Combined, INSUFFICIENT

Final Answer: E

GMAT assassins aren't born, they're made,
Rich

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag

Best Conversation Starters

1 lheiannie07 112 topics
2 ardz24 63 topics
3 LUANDATO 54 topics
4 Roland2rule 52 topics
5 swerve 47 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description GMATGuruNY

The Princeton Review Teacher

156 posts
2 image description Scott@TargetTestPrep

Target Test Prep

120 posts
3 image description Jeff@TargetTestPrep

Target Test Prep

106 posts
4 image description EconomistGMATTutor

The Economist GMAT Tutor

92 posts
5 image description Rich.C@EMPOWERgma...

EMPOWERgmat

91 posts
See More Top Beat The GMAT Experts