It is currently 12 Dec 2017, 19:31

### GMAT Club Daily Prep

#### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Working together at their respective rates, two hoses fill a pool in 2

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 42575

Kudos [?]: 135405 [0], given: 12692

Working together at their respective rates, two hoses fill a pool in 2 [#permalink]

### Show Tags

08 Aug 2017, 00:22
00:00

Difficulty:

5% (low)

Question Stats:

92% (00:51) correct 8% (00:37) wrong based on 61 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
[Reveal] Spoiler: OA

_________________

Kudos [?]: 135405 [0], given: 12692

Director
Joined: 04 Dec 2015
Posts: 696

Kudos [?]: 334 [0], given: 261

Location: India
Concentration: Technology, Strategy
Schools: ISB '19, IIMA , IIMB, XLRI
WE: Information Technology (Consulting)
Re: Working together at their respective rates, two hoses fill a pool in 2 [#permalink]

### Show Tags

08 Aug 2017, 00:35
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

$$\frac{1}{3} + \frac{1}{B} = \frac{1}{2}$$

$$\frac{1}{B} = \frac{1}{2} - \frac{1}{3} = \frac{3-2}{6} = \frac{1}{6}$$

$$B = 6$$ hours

Therefore $$B$$ can fill the pool alone in $$6$$ hours.

Kudos [?]: 334 [0], given: 261

Director
Joined: 18 Aug 2016
Posts: 597

Kudos [?]: 179 [0], given: 136

GMAT 1: 630 Q47 V29
Re: Working together at their respective rates, two hoses fill a pool in 2 [#permalink]

### Show Tags

08 Aug 2017, 00:37
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

Kudos [?]: 179 [0], given: 136

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 10379

Kudos [?]: 3683 [0], given: 173

Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Re: Working together at their respective rates, two hoses fill a pool in 2 [#permalink]

### Show Tags

04 Dec 2017, 13:40
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.

[Reveal] Spoiler:
E

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

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

# Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save \$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************

Kudos [?]: 3683 [0], given: 173

Re: Working together at their respective rates, two hoses fill a pool in 2   [#permalink] 04 Dec 2017, 13:40
Display posts from previous: Sort by

# Working together at their respective rates, two hoses fill a pool in 2

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.