Find all School-related info fast with the new School-Specific MBA Forum

It is currently 26 Jul 2014, 05:26

Close

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
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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

A swimming pool has three pumps, A, B and C. Working

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
GMAT Instructor
avatar
Joined: 04 Jul 2006
Posts: 1270
Location: Madrid
Followers: 23

Kudos [?]: 113 [0], given: 0

A swimming pool has three pumps, A, B and C. Working [#permalink] New post 14 Sep 2006, 13:22
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
A swimming pool has three pumps, A, B and C. Working together at their constant rates, A and B can drain the swimming pool in 10 hours, whereas A and C can drain the pool in 12 hours. How long does it take A to drain the pool?

(1) B and C, working together, can drain the pool in 15 hours.
(2) The time it would take 3 B's to drain the pool is equal to the time it would take 4 C's to do so.

Last edited by kevincan on 14 Sep 2006, 13:42, edited 1 time in total.
SVP
SVP
User avatar
Joined: 01 May 2006
Posts: 1816
Followers: 8

Kudos [?]: 86 [0], given: 0

GMAT Tests User
 [#permalink] New post 14 Sep 2006, 13:26
In statment (1), is it A C working together or B C ? :)
SVP
SVP
User avatar
Joined: 24 Aug 2006
Posts: 2137
Followers: 3

Kudos [?]: 82 [0], given: 0

GMAT Tests User
Re: DS: Swimming Pool Drainage [#permalink] New post 14 Sep 2006, 13:56
kevincan wrote:
A swimming pool has three pumps, A, B and C. Working together at their constant rates, A and B can drain the swimming pool in 10 hours, whereas A and C can drain the pool in 12 hours. How long does it take A to drain the pool?

(1) B and C, working together, can drain the pool in 15 hours.
(2) The time it would take 3 B's to drain the pool is equal to the time it would take 4 C's to do so.



Answer is D

I will explain later. B gets tricky.
SVP
SVP
User avatar
Joined: 24 Aug 2006
Posts: 2137
Followers: 3

Kudos [?]: 82 [0], given: 0

GMAT Tests User
Re: DS: Swimming Pool Drainage [#permalink] New post 14 Sep 2006, 17:44
kidderek wrote:
kevincan wrote:
A swimming pool has three pumps, A, B and C. Working together at their constant rates, A and B can drain the swimming pool in 10 hours, whereas A and C can drain the pool in 12 hours. How long does it take A to drain the pool?

(1) B and C, working together, can drain the pool in 15 hours.
(2) The time it would take 3 B's to drain the pool is equal to the time it would take 4 C's to do so.



Answer is D

I will explain later. B gets tricky.


Hmmm, I might be over thinking, but I am going to retract the D answer and get back to it.
VP
VP
User avatar
Joined: 02 Jun 2006
Posts: 1270
Followers: 2

Kudos [?]: 35 [0], given: 0

GMAT Tests User
 [#permalink] New post 14 Sep 2006, 18:57
Given
Ra = 1/Ta
Rb = 1/Tb
Rc = 1/Tc

Where Ta, Tb & Tc are times to drain the pool by themselves.

Given
Ra + Rb = 1/10 .... (1)

Rb + Rc = 1/12 ... (2)

=> Rb -Rc = 1/60 .... (3)

S1:
Rb + Rc = 1/15

From (3) and above eqn we can find Rb.

From Rb and (1) we can find Ra.
Sufficient.

S2:
3Rb = 4Rc

3Rb - 4Rc = 0

From (2) multiplying by 4:

4Rb +4Rc = 1/3
3Rb -4Rc = 0

Can solve for Rb... and from (1) can solve for Ra.

Sufficient.

Answer: D
Director
Director
avatar
Joined: 23 Jun 2005
Posts: 847
GMAT 1: 740 Q48 V42
Followers: 4

Kudos [?]: 21 [0], given: 1

GMAT Tests User
 [#permalink] New post 14 Sep 2006, 19:42
Arrived at D, but didn't work it out as detailed as Haas_mba07.
Statement 1: Gives you B+C. Imagine 2As, 1 B and 1 C [(A+B) and (A+C)] draining the tank and two more pumps (B+C) pouring in water, and you effectively negate B and C and can figure out how long it takes A to drain the tank. So, sufficient.
Statement 2: Gives you B in terms of C or vice versa. Substitute appropriately to find out A.

Wow! Typing this out took much longer than figuring it out in my head. Hope it makes sense to most people at least.
Manager
Manager
User avatar
Joined: 13 Sep 2006
Posts: 212
Followers: 2

Kudos [?]: 1 [0], given: 0

GMAT Tests User
 [#permalink] New post 14 Sep 2006, 20:51
D..for this reason...

1 and 2 result in 3 equations w/ 3 distinct variables.
Intern
Intern
avatar
Joined: 27 Aug 2006
Posts: 34
Followers: 0

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 25 Sep 2006, 00:47
Hass_Mba or Anyone,

Pardon my lack of knowledge ,but how did u get to #3 Higlighted below

--Snippet from solution earlier
Given
Ra = 1/Ta
Rb = 1/Tb
Rc = 1/Tc

Where Ta, Tb & Tc are times to drain the pool by themselves.

Given
Ra + Rb = 1/10 .... (1)

Rb + Rc = 1/12 ... (2)

=> Rb -Rc = 1/60 .... (3)

could u pls explain ?
thanks
  [#permalink] 25 Sep 2006, 00:47
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic A, B and C start swimming in a pool simultaneously from the b2bt 5 09 Mar 2014, 21:31
2 Experts publish their posts in the topic Pump A can empty a pool in A minutes, and pump B can empty gmatgambler 8 24 Jan 2014, 06:13
8 Experts publish their posts in the topic Marge has 3 pumps for filling her swimming pool. When all 3 Rock750 5 10 Feb 2013, 06:11
1 Experts publish their posts in the topic Working together, 7 identical pumps can empty a pool in 6 kapsycumm 5 17 Oct 2012, 20:32
Pumps A,B, and C operate at constant rates. Pumps A & B, zamzim 4 12 Nov 2006, 07:28
Display posts from previous: Sort by

A swimming pool has three pumps, A, B and C. Working

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.