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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

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

A

B

C

D

E

Difficulty:

55% (hard)

Question Stats:

72% (03:56) correct
28% (03:57) wrong based on 285 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

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.

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.

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.

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

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.
_________________

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.
_________________

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?

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)
_________________

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
_________________

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

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.

gmatclubot

Re: With both valves open, the pool will be filled with water in
[#permalink]
25 Sep 2016, 10:09

Its been long time coming. I have always been passionate about poetry. It’s my way of expressing my feelings and emotions. And i feel a person can convey...

Written by Scottish historian Niall Ferguson , the book is subtitled “A Financial History of the World”. There is also a long documentary of the same name that the...

Post-MBA I became very intrigued by how senior leaders navigated their career progression. It was also at this time that I realized I learned nothing about this during my...