• 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
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • 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
  • 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
  • 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
  • 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

Pipe A runs 30 liters of water per minute into a pool that h

This topic has 2 expert replies and 0 member replies

Pipe A runs 30 liters of water per minute into a pool that h

Post Thu Nov 09, 2017 4:33 pm
Pipe A runs 30 liters of water per minute into a pool that has a total volume of 3,600 liters. Pipe B fills a third of the pool in 6 hours.

Working together how long will it take both pipes to fill the pool?

A. 2 hours and 36 minutes
B. 1.5 hours
C. 9 hours and 12 minutes
D. 15 hours
E. 1 hour and 48 minutes.

OA: E

Is there a strategic approach to this question?

  • +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!

GMAT/MBA Expert

Post Fri Nov 10, 2017 8:45 am
ardz24 wrote:
Pipe A runs 30 liters of water per minute into a pool that has a total volume of 3,600 liters. Pipe B fills a third of the pool in 6 hours.

Working together how long will it take both pipes to fill the pool?

A. 2 hours and 36 minutes
B. 1.5 hours
C. 9 hours and 12 minutes
D. 15 hours
E. 1 hour and 48 minutes.
Let's determine the COMBINED RATE of the two pipes

Given: Pipe A's RATE = 30 liters per minute
This is equivalent to 1800 liters per HOUR

Pipe B fills a third of the pool in 6 hours
So, Pipe B fills the ENTIRE pool (3600 liters) in 18 hours
Rate = Output/time
= 3600/18
= 200 liters per hour

COMBINED RATE = 1800 + 200
= 2000 liters per hour


Working together how long will it take both pipes to fill the pool?
Time = output/rate
= 3600/2000
= 36/20 hours
= 9/5 hours
= 1 4/5 hours
= 1 hour and 48 minutes
= 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
Thanked by: ardz24
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!
Post Thu Nov 09, 2017 9:18 pm
ardz24 wrote:
Pipe A runs 30 liters of water per minute into a pool that has a total volume of 3,600 liters. Pipe B fills a third of the pool in 6 hours.

Working together how long will it take both pipes to fill the pool?

A. 2 hours and 36 minutes
B. 1.5 hours
C. 9 hours and 12 minutes
D. 15 hours
E. 1 hour and 48 minutes.

OA: E

Is there a strategic approach to this question?
For pipe A, at the rate of 30 lit/min, it will take 3600/30 = 120 min = 2 hours, working individually, to fill the pool.
Since Pipe B fills one-third of the pool in 6 hours, it will take 6*3 = 18 hours, working individually, to fill the pool.

Working together, both the pipes will fill 1/2 + 1/18 = 5/9 part of the pool in an hour.

Thus, it will take both the pipes will take 9/5 = 1 hr 48 min. to fill the pool.

The correct answer: E

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Singapore | Doha | Lausanne | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.

  • +1 Upvote Post
  • Quote
  • Flag
Thanked by: ardz24

Best Conversation Starters

1 Roland2rule 174 topics
2 lheiannie07 110 topics
3 ardz24 64 topics
4 LUANDATO 56 topics
5 swerve 46 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

150 posts
2 image description Jeff@TargetTestPrep

Target Test Prep

145 posts
3 image description Rich.C@EMPOWERgma...

EMPOWERgmat

116 posts
4 image description GMATGuruNY

The Princeton Review Teacher

103 posts
5 image description Scott@TargetTestPrep

Target Test Prep

98 posts
See More Top Beat The GMAT Experts