Oct 22 08:00 AM PDT  09:00 AM PDT Join to learn strategies for tackling the longest, wordiest examples of Counting, Sets, & Series GMAT questions Oct 22 09:00 AM PDT  10:00 AM PDT Watch & learn the Do's and Don’ts for your upcoming interview Oct 22 08:00 PM PDT  09:00 PM PDT On Demand for $79. For a score of 4951 (from current actual score of 40+) AllInOne Standard & 700+ Level Questions (150 questions) Oct 23 08:00 AM PDT  09:00 AM PDT Join an exclusive interview with the people behind the test. If you're taking the GMAT, this is a webinar you cannot afford to miss! Oct 26 07:00 AM PDT  09:00 AM PDT Want to score 90 percentile or higher on GMAT CR? Attend this free webinar to learn how to prethink assumptions and solve the most challenging questions in less than 2 minutes. Oct 27 07:00 AM EDT  09:00 AM PDT Exclusive offer! Get 400+ Practice Questions, 25 Video lessons and 6+ Webinars for FREE.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58410

Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
08 Aug 2017, 01:22
Question Stats:
91% (00:54) correct 9% (01:10) wrong based on 136 sessions
HideShow timer Statistics
Working together at their respective rates, two hoses fill a pool in 2 hours. If one of the hoses, working alone, could fill the pool in 3 hours, how long would it take the other hose to fill the pool alone? A. 2 hours B. 3 hours C. 4 hours D. 5 hours E. 6 hours
Official Answer and Stats are available only to registered users. Register/ Login.
_________________



Director
Joined: 04 Dec 2015
Posts: 743
Location: India
Concentration: Technology, Strategy
Schools: HEC Sept19 intake, ISB '19, Rotman '21, NUS '21, IIMA , IIMB, NTU '20, Bocconi '22, XLRI, Trinity MBA '20, Smurfit "21
WE: Information Technology (Consulting)

Re: Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
08 Aug 2017, 01:35
Bunuel wrote: Working together at their respective rates, two hoses fill a pool in 2 hours. If one of the hoses, working alone, could fill the pool in 3 hours, how long would it take the other hose to fill the pool alone?
A. 2 hours B. 3 hours C. 4 hours D. 5 hours E. 6 hours Let the hoses be \(A\) and \(B\). Given \(A\) and \(B\) hoses together can fill a pool in \(2\) hours. Therefore \(1\) hour work of \(A\) and \(B\) together is equal to. \(\frac{1}{A} + \frac{1}{B} = \frac{1}{2}\) Given \(A\) could fill the pool in \(3\) hours alone. Therefore, \(A = 3\) hours \(\frac{1}{3} + \frac{1}{B} = \frac{1}{2}\) \(\frac{1}{B} = \frac{1}{2}  \frac{1}{3} = \frac{32}{6} = \frac{1}{6}\) \(B = 6\) hours Therefore \(B\) can fill the pool alone in \(6\) hours. Answer (E)...



Current Student
Joined: 18 Aug 2016
Posts: 602
Concentration: Strategy, Technology
GMAT 1: 630 Q47 V29 GMAT 2: 740 Q51 V38

Re: Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
08 Aug 2017, 01:37
Bunuel wrote: Working together at their respective rates, two hoses fill a pool in 2 hours. If one of the hoses, working alone, could fill the pool in 3 hours, how long would it take the other hose to fill the pool alone?
A. 2 hours B. 3 hours C. 4 hours D. 5 hours E. 6 hours Pool is 6 units Hose A + Hose B = 3 units/hr Hose A = 2 units/hr Hose B = 1 unit/hr Time = 6/1 = 6 hrs E
_________________
We must try to achieve the best within us
Thanks Luckisnoexcuse



EMPOWERgmat Instructor
Status: GMAT Assassin/CoFounder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15309
Location: United States (CA)

Re: Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
04 Dec 2017, 14:40
Hi All, This question is a standard example of a Work Formula question (with 2 'entities' working on a job together). When this type of question has no 'quirks' to it (such as 3 or more entities or one of the entities stops working partway through the job), you can use the Work Formula to answer it: Work = (A)(B)/(A+B) = amount of time to complete the job while working together (where A and B are the two individual times it takes to do the job). In this prompt, we know that one of the hoses takes 3 hours to do the job alone and that the two hoses (working together) can complete the job in 2 hours.... (3)(B)/(3+B) = 2 hours 3B = (2)(3+B) 3B = 6 + 2B B = 6 hours Thus, it would take the second hose 6 hours to fill the pool by itself. Final Answer: GMAT assassins aren't born, they're made, Rich
_________________
Contact Rich at: Rich.C@empowergmat.comThe Course Used By GMAT Club Moderators To Earn 750+ souvik101990 Score: 760 Q50 V42 ★★★★★ ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★



Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8125
Location: United States (CA)

Re: Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
04 Jan 2018, 11:12
Bunuel wrote: Working together at their respective rates, two hoses fill a pool in 2 hours. If one of the hoses, working alone, could fill the pool in 3 hours, how long would it take the other hose to fill the pool alone?
A. 2 hours B. 3 hours C. 4 hours D. 5 hours E. 6 hours We can let n = the time, in hours, it takes the other hose to fill the pool alone. Thus, the rate of that hose = 1/n. Since the rate of the known hose = 1/3 and the combined rate = 1/2, we have: 1/n + 1/3 = 1/2 Multiplying by 6n, we have: 6 + 2n = 3n 6 = n Thus, the other hose takes 6 hours to fill the pool. Answer: E
_________________
5star rated online GMAT quant self study course See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews If you find one of my posts helpful, please take a moment to click on the "Kudos" button.



Senior PS Moderator
Joined: 26 Feb 2016
Posts: 3334
Location: India
GPA: 3.12

Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
04 Jan 2018, 13:43
Bunuel wrote: Working together at their respective rates, two hoses fill a pool in 2 hours. If one of the hoses, working alone, could fill the pool in 3 hours, how long would it take the other hose to fill the pool alone?
A. 2 hours B. 3 hours C. 4 hours D. 5 hours E. 6 hours Since one of the hoses fills the pool in 3 hours and both the hoses fill the pool in 2 hour, we should assume a number divisible by both these numbers to be the total capacity of the pool. Let that be 60 units. Let the hose which can fill the pool alone in 3 hours be hose A, so the rate of work is 20 units/hour. Similarly, both the hoses can fill the pool in 2 hours, and must fill 30 units/hour. Hence, the other hose must be filling the pool at the rate of 10 units/hr Therefore, the time taken to fill the entire pool is \(\frac{60}{10}\) (6 hours  Option E)
_________________
You've got what it takes, but it will take everything you've got



GMAT Club Legend
Joined: 12 Sep 2015
Posts: 4016
Location: Canada

Re: Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
10 Jan 2018, 08:26
Bunuel wrote: Working together at their respective rates, two hoses fill a pool in 2 hours. If one of the hoses, working alone, could fill the pool in 3 hours, how long would it take the other hose to fill the pool alone?
A. 2 hours B. 3 hours C. 4 hours D. 5 hours E. 6 hours Another approach is to assign a nice value to the job. In this case, we need a value that works well with the given information (2 hours and 3 hours). So, let's say the job consists of filling a pool containing 6 liters of water One of the hoses, working alone, takes 3 hours to fill the pool We'll call this hose A. Let A = the rate of work of this hose If it takes 3 hours for this hose to fill a 6liter pool, then.... A = 6/3 = 2 liters per hour (since rate = output/time) Working together at their respective rates, two hoses fill a pool in 2 hours. Let B = the rate of work of the other hose So, the COMBINED rate = A+B If it takes 2 hours for the combined hoses to fill a 6liter pool then.... A+B = 6/2 = 3 liters per hour (since rate = output/time) So, if A = 2 liters per hour, and A+B = 3 liters per hour Then we can see that B = 1 liter per hour How long would it take the other hose (hose B) to fill the pool alone? Time = output/rate = 6/ 1 = 6 hours Answer: E Cheers, Brent
_________________
Test confidently with gmatprepnow.com



Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4777
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)

Re: Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
Show Tags
10 Jan 2018, 09:03
Bunuel wrote: Working together at their respective rates, two hoses fill a pool in 2 hours. If one of the hoses, working alone, could fill the pool in 3 hours, how long would it take the other hose to fill the pool alone?
A. 2 hours B. 3 hours C. 4 hours D. 5 hours E. 6 hours Let the total capacity of the pool be 6 units Efficiency of A + B = 3 units/hr Efficiency of B = 2 units/hr So, Efficiency of A = 1 unit/hr Thus, time required to fill the pool alone is 6 hours, answer will be (E)
_________________




Re: Working together at their respective rates, two hoses fill a pool in 2
[#permalink]
10 Jan 2018, 09:03






