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

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • 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
  • 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
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • 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
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh

Difficult Math Problem #88 - Geometry

This topic has 1 expert reply and 4 member replies
800guy Master | Next Rank: 500 Posts Default Avatar
Joined
27 Jun 2006
Posted:
354 messages
Followed by:
5 members
Upvotes:
11

Difficult Math Problem #88 - Geometry

Post Fri Jan 19, 2007 9:32 am
Which of the sets of numbers can be used as the lengths of the sides of a triangle?

I. [5,7,12]
II. [2,4,10]
III. [5,7,9]

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


from 'difficult math problems' problem set. OA coming after some people attempt answers/explanations

  • +1 Upvote Post
  • Quote
  • Flag
Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
Top Reply
Post Sun Dec 03, 2017 8:26 am
The longest side of a triangle must be less than the sum of the two other sides.
Option I {5, 7, 12}
The longest side is 12
and 12 = 5+7
Since, 12 is not less than 5+7 thus thisoption is invalid.

Option II : {2, 4, 10}
The longest side is 10 which is greater than 2+4=6.Thus, this option is invalid.

Option III : {5, 7, 9}
The longest side is 9, which is less than 5+7=12. Since this agrees with the rule stated above, this option is valid.
Only III is correct.
Therefore, the answer is B.

  • +1 Upvote Post
  • Quote
  • Flag
Top Reply
Post Sun Dec 03, 2017 7:24 pm
Hi All,

Roland2rule's approach to this question is spot-on, so I won't rehash any of that math here. It's worth noting that Roman Numeral questions are often designed so that you don't necessarily have to work through all 3 Roman Numerals... IF you're paying attention to how the answer choices are written. Here, once you've proven that Roman Numeral 1 and Roman Numeral 2 are not possibilities, you can select the correct answer (and you don't even have to work on Roman Numeral 3).

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

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag
Post Sun Dec 03, 2017 8:26 am
The longest side of a triangle must be less than the sum of the two other sides.
Option I {5, 7, 12}
The longest side is 12
and 12 = 5+7
Since, 12 is not less than 5+7 thus thisoption is invalid.

Option II : {2, 4, 10}
The longest side is 10 which is greater than 2+4=6.Thus, this option is invalid.

Option III : {5, 7, 9}
The longest side is 9, which is less than 5+7=12. Since this agrees with the rule stated above, this option is valid.
Only III is correct.
Therefore, the answer is B.

  • +1 Upvote Post
  • Quote
  • Flag
Post Sun Dec 03, 2017 7:24 pm
Hi All,

Roland2rule's approach to this question is spot-on, so I won't rehash any of that math here. It's worth noting that Roman Numeral questions are often designed so that you don't necessarily have to work through all 3 Roman Numerals... IF you're paying attention to how the answer choices are written. Here, once you've proven that Roman Numeral 1 and Roman Numeral 2 are not possibilities, you can select the correct answer (and you don't even have to work on Roman Numeral 3).

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

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag
800guy Master | Next Rank: 500 Posts Default Avatar
Joined
27 Jun 2006
Posted:
354 messages
Followed by:
5 members
Upvotes:
11
Post Mon Jan 22, 2007 4:57 pm
OA:

For any side of a triangle. Its length must be greater than the difference between the other two sides, but less than the sum of the other two sides.
Answer is B

  • +1 Upvote Post
  • Quote
  • Flag

Best Conversation Starters

1 lheiannie07 116 topics
2 LUANDATO 67 topics
3 swerve 66 topics
4 ardz24 61 topics
5 AAPL 59 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description Scott@TargetTestPrep

Target Test Prep

213 posts
2 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

177 posts
3 image description Jeff@TargetTestPrep

Target Test Prep

168 posts
4 image description Rich.C@EMPOWERgma...

EMPOWERgmat

133 posts
5 image description GMATGuruNY

The Princeton Review Teacher

126 posts
See More Top Beat The GMAT Experts