• NEW! FREE Beat The GMAT Quizzes
Hundreds of Questions Highly Detailed Reporting Expert Explanations
• 7 CATs FREE!
If you earn 100 Forum Points

Engage in the Beat The GMAT forums to earn
100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote Working alone, pump A can empty a pool in 3 hours... tagged by: BTGmoderatorLU This topic has 1 expert reply and 0 member replies Top Member Working alone, pump A can empty a pool in 3 hours... Working alone, pump A can empty a pool in 3 hours. Working alone, pump B can empty the same pool in 2 hours. Working together, how how many minutes will it take pump A and pump B to empty the pool? (A) 72 (B) 75 (C) 84 (D) 96 (E) 108 The OA is A. I'm confused with this PS question. Experts, any suggestion? I don't know how can I solve it. Thanks in advance. GMAT/MBA Expert GMAT Instructor Joined 04 Oct 2017 Posted: 551 messages Followed by: 11 members Upvotes: 180 Top Reply Hello LUANDATO. Let's take a look at your question. Working alone, pump A can empty a pool in 3 hours, it implies that pump A wor at a rate 1/3 pool/hour. Working alone, pump B can empty a pool in 2 hours, it implies that pump A wor at a rate 1/2 pool/hour. Working together the rate will be equal to $$\frac{1}{3}+\frac{1}{2}=\frac{5}{6}\ \text{pool per hour}$$. Now we have the following: $$\frac{5\ }{6\ }\ \frac{pool}{60\ \min}=1\ \frac{pool}{x}\ \Leftrightarrow\ x=72\ \min.$$ This is why the correct answer is the option A=72. I hope this answer may help you. I'm available if you'd like a follow-up. Regards. _________________ GMAT Prep From The Economist We offer 70+ point score improvement money back guarantee. Our average student improves 98 points. 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. • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Award-winning private GMAT tutoring Register now and save up to$200

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• FREE GMAT Exam
Know how you'd score today for \$0

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

Top First Responders*

1 Brent@GMATPrepNow 40 first replies
2 Ian Stewart 40 first replies
3 Scott@TargetTestPrep 39 first replies
4 Jay@ManhattanReview 28 first replies
5 GMATGuruNY 25 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

Most Active Experts

1 Scott@TargetTestPrep

Target Test Prep

159 posts
2 Max@Math Revolution

Math Revolution

90 posts
3 Brent@GMATPrepNow

GMAT Prep Now Teacher

58 posts
4 Ian Stewart

GMATiX Teacher

49 posts
5 GMATGuruNY

The Princeton Review Teacher

38 posts
See More Top Beat The GMAT Experts