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

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • 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
  • 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
  • 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

Jason can stack two shelves in 3 hours and Maria can stack

This topic has 3 expert replies and 0 member replies

Jason can stack two shelves in 3 hours and Maria can stack

Post

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Difficult



Magoosh

Jason can stack two shelves in 3 hours and Maria can stack three shelves in 2 hours. How long will it take them together, working at a constant rate, to stack thirteen shelves?

A. 5 hours
B. 6 hours
C. 6.5 hours
D. 11 hours
E. 12 hours

OA B.

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post
Hi All,

We're told that Jason can stack 2 shelves in 3 hours and Maria can stack 3 shelves in 2 hours. We're asked how long will it take them together, working at their constant rates, to stack thirteen shelves. This question is a 'rate' question, so you can work through the math in a number of different ways. Here's an approach that puts both rates in terms of 'output per hour':

Jason stacks 2 shelves every 3 hours, so he stacks 2/3 of a shelf per hour.
Maria stacks 3 shelves every 2 hours, so he stacks 3/2 of a shelf per hour.
Combined, they stack 2/3 + 3/2 = 4/6 + 9/6 = 13/6 shelves per hour.

We're asked how long it would take for the two to stock 13 shelves....

(X)(13/6 shelves/hour) = 13 shelves
X = 13(6/13) = 6 hours

Final Answer: B

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

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post
AAPL wrote:
Magoosh

Jason can stack two shelves in 3 hours and Maria can stack three shelves in 2 hours. How long will it take them together, working at a constant rate, to stack thirteen shelves?

A. 5 hours
B. 6 hours
C. 6.5 hours
D. 11 hours
E. 12 hours
Let each shelf = 6 pounds.
Since Jason takes 3 hours to stack 2 6-pound shelves -- for a total of 12 pounds -- Jason's rate = 12/3 = 4 pounds per hour.
Since Maria takes 2 hours to stack 3 6-pound shelves -- for a total of 18 pounds -- Maria's rate = 18/2 = 9 pounds per hour.
Total weight of 13 6-pound shelves = 13*6 = 78 pounds.
Combined rate for Jason and Maria = 4+9 = 13 pounds per hour.
Time for Jason and Maria to stack the 13 shelves = 78/13 = 6 hours.

The correct answer is B.

_________________
Mitch Hunt
Private Tutor for the GMAT and GRE
GMATGuruNY@gmail.com

If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.

Available for tutoring in NYC and long-distance.
For more information, please email me at GMATGuruNY@gmail.com.
Student Review #1
Student Review #2
Student Review #3

  • +1 Upvote Post
  • Quote
  • Flag
Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.
Post
AAPL wrote:
Magoosh

Jason can stack two shelves in 3 hours and Maria can stack three shelves in 2 hours. How long will it take them together, working at a constant rate, to stack thirteen shelves?

A. 5 hours
B. 6 hours
C. 6.5 hours
D. 11 hours
E. 12 hours
The combined rate of Jason and Maria is 2/3 + 3/2 = 4/6 + 9/6 = 13/6.

So it takes them 13/(13/6) = 13 x 6/13 = 6 hours to stack 13 shelves.

Answer: B

_________________
Jeffrey Miller Head of GMAT Instruction

  • +1 Upvote Post
  • Quote
  • Flag

Top First Responders*

1 Jay@ManhattanReview 83 first replies
2 Brent@GMATPrepNow 68 first replies
3 fskilnik 55 first replies
4 GMATGuruNY 36 first replies
5 ceilidh.erickson 13 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 fskilnik

GMAT Teacher

199 posts
2 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

160 posts
3 image description Scott@TargetTestPrep

Target Test Prep

109 posts
4 image description Jay@ManhattanReview

Manhattan Review

95 posts
5 image description GMATGuruNY

The Princeton Review Teacher

90 posts
See More Top Beat The GMAT Experts