• Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • examPAL
    Most awarded test prep in the world
    Now free for 30 days

    Available with Beat the GMAT members only code

    MORE DETAILS
    examPAL
  • 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
  • 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
  • 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
  • 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

David has d books (OG16)

This topic has 2 expert replies and 0 member replies
boomgoesthegmat Senior | Next Rank: 100 Posts Default Avatar
Joined
25 Apr 2016
Posted:
93 messages
Upvotes:
1

David has d books (OG16)

Post Thu May 19, 2016 3:45 pm
David has d books, which is 3 times as many as Jeff and 1/2 as many as Paula. How many books do the three of them have altogether, in terms of d ?

A) (5/6)d
B) (7/3)d
C) (10/3)d
D) (7/2)d
E) (9/2)d

OA: C



Last edited by boomgoesthegmat on Thu May 19, 2016 4:30 pm; edited 1 time in total

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post Fri May 20, 2016 9:01 am
boomgoesthegmat wrote:
David has d books, which is 3 times as many as Jeff and 1/2 as many as Paula. How many books do the three of them have altogether, in terms of d ?

A) (5/6)d
B) (7/3)d
C) (10/3)d
D) (7/2)d
E) (9/2)d

OA: C
Rich has demonstrated the INPUT-OUTPUT approach. Here's an algebraic approach.

d = # of books that David has

David has 3 times as many books as Jeff
So, d/3 = # of books that Jeff has

David has 1/2 as many books as Paula
So, 2d = # of books that Paula has

How many books do the three of them have altogether, in terms of d ?
TOTAL # of books = d + d/3 + 2d
= 3d/3 + d/3 + 6d/3
= 10d/3
= C

---------------------------------

Rich and I have demonstrated the two methods (Algebraic and Input-Output) for solving a question type I call Variables in the Answer Choices.
If you'd like more information on these approaches, we have some videos:
- Variables in the Answer Choices - http://www.gmatprepnow.com/module/gmat-word-problems/video/933
- Tips for the Algebraic Approach - http://www.gmatprepnow.com/module/gmat-word-problems/video/934
- Tips for the Input-Output Approach - http://www.gmatprepnow.com/module/gmat-word-problems/video/935

Here are some more questions to practice with:
- http://www.beatthegmat.com/what-mistake-am-i-making-in-this-substitution-last-sunday-a-t276293.html
- http://www.beatthegmat.com/car-dealer-sales-t274136.html
- http://www.beatthegmat.com/ps-rate-times-t276107.html
- http://www.beatthegmat.com/to-find-the-least-perfect-square-t273338.html
- http://www.beatthegmat.com/y-dollars-from-the-rental-venture-t273031.html
- http://www.beatthegmat.com/meters-in-x-minutes-t273854.html
- http://www.beatthegmat.com/a-better-explanation-please-t279396.html


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 Thu May 19, 2016 4:28 pm
Hi boomgoesthegmat,

To start, there's a typo in your transcription - it's supposed to read "...and 1/2 as many as Paula...."

We can answer this question by TESTing VALUES or by doing algebra...

IF...
Jeff = 2 books
David = 6 books = D books
Paula = 12 books

The total number of books = 2+6+12 = 20

So we're looking for an answer that equals 20 when D=6. There's only one answer that matches...

Final Answer: C

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 71 topics
3 Roland2rule 69 topics
4 LUANDATO 53 topics
5 swerve 45 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description GMATGuruNY

The Princeton Review Teacher

154 posts
2 image description Rich.C@EMPOWERgma...

EMPOWERgmat

107 posts
3 image description Jeff@TargetTestPrep

Target Test Prep

106 posts
4 image description Scott@TargetTestPrep

Target Test Prep

98 posts
5 image description EconomistGMATTutor

The Economist GMAT Tutor

91 posts
See More Top Beat The GMAT Experts