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

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • The Princeton Review
    FREE GMAT Exam
    Know how you'd score today for $0

    Available with Beat the GMAT members only code

    MORE DETAILS
    The Princeton Review

G(x) is the greatest integer less

This topic has 2 expert replies and 0 member replies

G(x) is the greatest integer less

Post Thu Dec 28, 2017 5:05 am
G(x) is the greatest integer less than or equal to x and L(x) is the least integer greater than or equal to x. When x is not an integer, which of the following is the value of L(x)-G(x)?

A. -2
B. -1
C. 0
D. 1
E. 2

The OA is the option D.

How can I know the value of L(x)-G(x) without knowing the value of x?

Experts, may you help me here? I'd be thankful.

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Top Reply
Post Thu Dec 28, 2017 8:51 am
Hello Vjesus12.

Let's take a look at your question.

Let's suppose that x=5.2. Then $$G\left(x\right)=G\left(5.2\right)=5\ ;\ \ and\ \ \ \ L\left(x\right)=L\left(5.2\right)=6.$$ Therefore, $$L\left(x\right)-G\left(x\right)=1.$$ This situation happens every time that x is not an integer.

Hence, the correct solution is option D=1.

I hope this may help you.

Feel free to ask me again if you have a doubt.

Regards.

_________________
GMAT Prep From The Economist
We offer 70+ point score improvement money back guarantee.
Our average student improves 98 points.

  • +1 Upvote Post
  • Quote
  • Flag
Free 7-Day Test Prep with Economist GMAT Tutor - Receive free access to the top-rated GMAT prep course including a 1-on-1 strategy session, 2 full-length tests, and 5 ask-a-tutor messages. Get started now.

GMAT/MBA Expert

Post Thu Dec 28, 2017 10:01 am
Hi VJesus12,

We're told that G(X) is the greatest integer LESS THAN OR EQUAL to X and L(X) is the least integer GREATER THAN OR EQUAL to X. When X is NOT an integer, we're asked which of the following is the value of L(X)-G(X).

This question can be solved rather easily by TESTing VALUES (as the other explanation shows). It's also a fairly straight-forward 'concept' question - meaning that you don't have to do much math to answer it if you recognize the concepts involved.

We're told that X is NOT an integer, so the least integer that is GREATER THAN OR EQUAL to X would be the integer that is immediately to the "right" of X on a number line. In that same way, the greatest integer that is LESS THAN OR EQUAL to X would be the integer that is immediately to the 'left' of X on a number line. We're asked to calculate the larger number minus the smaller number - and that will always be 1.

Final Answer: D

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

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag

Top First Responders*

1 GMATGuruNY 108 first replies
2 Brent@GMATPrepNow 41 first replies
3 Rich.C@EMPOWERgma... 35 first replies
4 Jay@ManhattanReview 25 first replies
5 Scott@TargetTestPrep 11 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

Most Active Experts

1 image description GMATGuruNY

The Princeton Review Teacher

154 posts
2 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

129 posts
3 image description Scott@TargetTestPrep

Target Test Prep

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

EMPOWERgmat

81 posts
5 image description Max@Math Revolution

Math Revolution

80 posts
See More Top Beat The GMAT Experts