With both valves open, the pool will be filled with water in : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 23 Jan 2017, 15:58

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

With both valves open, the pool will be filled with water in

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

Hide Tags

Current Student
Joined: 11 May 2008
Posts: 556
Followers: 8

Kudos [?]: 175 [0], given: 0

With both valves open, the pool will be filled with water in [#permalink]

Show Tags

02 Sep 2008, 01:23
15
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

71% (03:57) correct 29% (03:57) wrong based on 284 sessions

HideShow timer Statistics

With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. If the second valve emits 50 cubic meters of water more than the first every minute, then what is the capacity of the pool?

A. 9000 cubic meters
B. 10500 cubic meters
C. 11750 cubic meters
D. 12000 cubic meters
E. 12500 cubic meters

M12-10
[Reveal] Spoiler: OA

Last edited by Bunuel on 22 Apr 2014, 23:15, edited 1 time in total.
Renamed the topic, edited the question, added the OA and moved to PS forum.
SVP
Joined: 17 Jun 2008
Posts: 1569
Followers: 11

Kudos [?]: 250 [0], given: 0

Re: work and time [#permalink]

Show Tags

02 Sep 2008, 01:58
1
This post was
BOOKMARKED
D. 12000 cubic meters.

If both hte valves fill the pool in 48 minutes and valve 1 only fills in 120 minutes then valve 2 alone will fill the pool in (48*120)/(120-48) = 80 minutes.

Now, if valve 1 admits x cubic meter of water per minute then the capacity of pool will be 120x and also 80 (x+50).

or, 120x = 80 (x + 50).
or x = 100.

Hence, the capacity of pool = 120x = 12000 cubic meters.
Manager
Affiliations: Beta Gamma Sigma
Joined: 14 Aug 2008
Posts: 210
Schools: Harvard, Penn, Maryland
Followers: 6

Kudos [?]: 65 [0], given: 3

Re: work and time [#permalink]

Show Tags

02 Sep 2008, 02:14
I got the same answer (D) but used a different technique.

I made two equations
120x = y
48(2X+50) = Y

then, I substituted the values in the answer choices (starting with the middle then working my way in either direction) with y being the answer.

so if 120x=12000, then 48(2x+50)=12000 as well, which it does if you do the math; whereas if you use any other answer choice the two equations are not equal (do not have the same value for x and y)
this could be done much easier if you could use a graphing calculator finding the intercept of both lines, but these are not permitted in the GMAT.
Intern
Joined: 16 Feb 2006
Posts: 30
Location: ZURICH
Followers: 0

Kudos [?]: 7 [0], given: 6

Re: work and time [#permalink]

Show Tags

02 Sep 2008, 03:53
With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. What is the capacity of the pool if every minute the second valve admits 50 cubic meters of water more than the first?

* 9000 cubic meters
* 10500 cubic meters
* 11750 cubic meters
* 12000 cubic meters
* 12500 cubic meters
With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. What is the capacity of the pool if every minute the second valve admits 50 cubic meters of water more than the first?

Soln:
Let volume filled by first valve per minute = Va cubic meter
As first valve takes 2hours to fill the pool
therefore volume of the pool = 120 x Va....(1)

Let the volume filled by second valve per minute = Vb cubic meter

Total volume filled by both the valves in 48 minutes = Va x 48 + Vb x 48
According to the condition of the problem

Vb = Va + 50

therefore total vulme filled in 48 minutes
Va x 48 + (Va+50) x 48 = volume of the pool = 120 Va ..from (1)
or, Va = 100

Total volume of the pool = 100 x 120 = 12000 cubic meters

Option D
_________________

TRY N TRY UNTIL U SUCCEED

Last edited by hksingh83 on 02 Sep 2008, 04:07, edited 1 time in total.
Senior Manager
Joined: 16 Jul 2008
Posts: 289
Schools: INSEAD Dec'10
Followers: 4

Kudos [?]: 16 [0], given: 4

Re: work and time [#permalink]

Show Tags

02 Sep 2008, 04:02
This one took me ages to solve.

1/48 = 1/120 + x --> solve for x. x = 1/80
y(1/80) = y(1/120) + 50 --> y = 12,000
_________________

http://applicant.wordpress.com/

Manager
Joined: 11 Sep 2013
Posts: 153
Concentration: Finance, Finance
Followers: 2

Kudos [?]: 94 [0], given: 156

Re: With both valves open, the pool will be filled with water in [#permalink]

Show Tags

22 Apr 2014, 21:31
Let 1st does in 1 minute =x so, in 120 min= 120x
2nd does=x+50
A/Q, 48x+48(x+50)=120x
X= 100
120x= 12000 (D)
Math Expert
Joined: 02 Sep 2009
Posts: 36618
Followers: 7101

Kudos [?]: 93565 [6] , given: 10578

Re: With both valves open, the pool will be filled with water in [#permalink]

Show Tags

22 Apr 2014, 23:15
6
This post received
KUDOS
Expert's post
10
This post was
BOOKMARKED
arjtryarjtry wrote:
With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. If the second valve emits 50 cubic meters of water more than the first every minute, then what is the capacity of the pool?

A. 9000 cubic meters
B. 10500 cubic meters
C. 11750 cubic meters
D. 12000 cubic meters
E. 12500 cubic meters

M12-10

Let the rate of the first valve be $$x$$ cubic meters per minute, then the rate of the second valve will be $$x+50$$ cubic meters per minute.

As both valves open fill the pool in 48 minutes then the capacity of the pool equals to $$C=time*combined \ rate=48(x+x+50)=48(2x+50)$$;
But as the first valve alone fills the pool in 2 hours (120 minutes) then the capacity of the pool also equals to $$C=time*rate=120x$$;

So, $$120x=48(2x+50)$$ --> $$x=100$$ --> $$C=120x=12,000$$.

Answer: D.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13522
Followers: 577

Kudos [?]: 163 [0], given: 0

Re: With both valves open, the pool will be filled with water in [#permalink]

Show Tags

23 Apr 2015, 18:01
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13522
Followers: 577

Kudos [?]: 163 [0], given: 0

Re: With both valves open, the pool will be filled with water in [#permalink]

Show Tags

24 Apr 2016, 06:06
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7130
Location: Pune, India
Followers: 2140

Kudos [?]: 13706 [2] , given: 222

With both valves open, the pool will be filled with water in 48 minute [#permalink]

Show Tags

17 May 2016, 20:57
2
This post received
KUDOS
Expert's post
Responding to a pm:

With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. What is the capacity of the pool if every minute the second valve admits 50 cubic meters of water more than the first?

(A) 9000 cubic meters
(B) 10500 cubic meters
(C) 11750 cubic meters
(D) 12000 cubic meters
(E) 12500 cubic meters

Normally, I would do this question the algebra way (I wouldn't use ratios here because partial data is in time and partial in work form):

Say, capacity of the pool is x cubic meters. Consider time in minutes.

First valve rate = Work/Time = x/120

Second valve rate = x/120 + 50

Combined rate = x/48

x/48 = x/120 + x/120 + 50

x/48 - x/60 = 50

x/4 - x/5 = 12*50

x = 12*50*20 = 12000

But if I am short on time, I can take a guess.

Most probably, the rate of work will be an integer .... cubic meters per minute. The additional rate of valve 2 is 50 cubic meters per minute so it is unlikely that rate of valve 1 will be something like 150.38 cubic meters per min. It will most probably be an integer.

Assuming that, I see that only option (D) is divisible by 48.
(48 has four 2s. 9000 has three 2s, 10500 has two 2s, 11750 has one 2 and 12500 has two 2s)

So most probably answer will be 12000. Let's check.

12000/48 = 250
12000/120 = 100
Valve 1 rate is 100 cubic meters per min. Valve 2 rate is 150 cubic meters per min.
Everything matches.
Answer (D)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for \$199

Veritas Prep Reviews

Verbal Forum Moderator
Joined: 02 Aug 2009
Posts: 4246
Followers: 331

Kudos [?]: 3477 [0], given: 101

With both valves open, the pool will be filled with water in [#permalink]

Show Tags

17 May 2016, 21:22
arjtryarjtry wrote:
With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. If the second valve emits 50 cubic meters of water more than the first every minute, then what is the capacity of the pool?

A. 9000 cubic meters
B. 10500 cubic meters
C. 11750 cubic meters
D. 12000 cubic meters
E. 12500 cubic meters

M12-10

Hi,

I would think of this in TWO ways if I had to do this Qs WITHOUT getting into serious calculation..

1) USE of CHOICES, as also explained above-
Very helpful in many calculations..
Ofcourse here, we believe that the speed, x here, must be integer..
so total = 48(x+x+50)..
so our answer should be a multiple of 48 or 3*16...
C and E are not multiple of 3..
A and B are multiples of 3, but not of 16..
D

2) second method..
In 48 minutes, the faster valve fills up 48*50=2400 more than 1st...
If both took same time as first,that is same speed, the tank would have been filled in 1 hour..

so in 60 - 48= 12 minutes, both would have filled 2400 cum..
BUT first one alone will fill it up in 12*2 = 24 mins...
if the first fills up 2400 in 24 mins..
it will fill 100 in 1 min and 12000 in 120 mins or 2 hours..
so Capacity of tank = 12000cum

D
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

Intern
Joined: 28 Aug 2015
Posts: 20
Location: Norway
WE: Information Technology (Consulting)
Followers: 0

Kudos [?]: 7 [0], given: 8

With both valves open, the pool will be filled with water in [#permalink]

Show Tags

25 Sep 2016, 06:45
Maybe you could try this way

Let us consider 240 unit water filled by valve.
(I took the LCM of 48 and 120 minute - 2 Hour).

Valve A - 2 Hour - 120 minute.
Rate - 2 unit/minute (As we have consider total unit 240 and valve A took 120 minute, so rate is 240/120 = 2.)
Valve A+B - 48 Minute.
Rate - 5 unit/minute (as specified above)

So, Value B alone takes 3 unit/minute. (5 unit/minute of a+b together - 2 unit/minute A alone.)
So time taken by B to fill 240 unit of tank is 80 minute. (240/3 - 80 minute ).
Now, as per question second valve emits 50 cubic meters of water more than the first every minute.
Every minute water emit by valve B is :- 50 * 3 = 150 cubic meter/ minute. so for 80 minute - 150 * 80 = 12000 cubic meter.
_________________

Thanks
Sumit kumar
If you like my post Kudos Please

Senior Manager
Joined: 07 Dec 2014
Posts: 499
Followers: 3

Kudos [?]: 82 [0], given: 2

Re: With both valves open, the pool will be filled with water in [#permalink]

Show Tags

25 Sep 2016, 10:09
With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. If the second valve emits 50 cubic meters of water more than the first every minute, then what is the capacity of the pool?

A. 9000 cubic meters
B. 10500 cubic meters
C. 11750 cubic meters
D. 12000 cubic meters
E. 12500 cubic meters

let c=capacity of pool
c/120+(c/120)+50=c/48
.5c=6000
c=12,000 cubic meters
D.
Re: With both valves open, the pool will be filled with water in   [#permalink] 25 Sep 2016, 10:09
Similar topics Replies Last post
Similar
Topics:
1 A pipe fills a pool in 3.5 hours. If the flow of water is changed so 3 03 Oct 2016, 22:33
9 A small pool filled only with water will require an addition 6 28 Jul 2013, 23:01
20 An empty pool being filled with water at a constant rate 15 20 Dec 2012, 04:53
61 With both inlets open, a water tank will be filled with wate 10 31 Oct 2011, 01:07
11 A pump started filling an empty pool with water and continue 8 20 Nov 2008, 10:30
Display posts from previous: Sort by

With both valves open, the pool will be filled with water in

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

 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®.