Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

This is from the GMATPrep Practice Test (they don't provide answer exps, so I'm trying to figure out how to do this problem)

*************
Two water pumps, working simultaneously at their respective rates, took exactly 4 hrs to fill a certain swimming pool. If the constant rate of one pump was 1.5 times the constant rate of the other pump, how many hours would it have taken the faster pump to fill the pool if it had worked alone at its constant rate

a) 5
b) 16/3
c) 11/2
d) 6
e) 20/3

The answer is E. Just not sure how to set this up.

I figured it was

1.5x + x = 4 hrs, where x equaled the constant rate. But going down this path doesnâ€™t seem to workâ€¦

Hallo,
Think that it is 20/3.
(1/R1)+(1/R2)=1/4
R1=1,5*R2
substitute and get
[10r2-(1,5r2)^2]/(6r2)^2=0
now denomionator can not be 0, cause division by 0 is not defined.
Equate nominator with 0 and get r2*(10-1,5r2)=0 so r2=20/3
regards