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:
A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
08 Oct 2011, 16:42
1
This post received KUDOS
00:00
A
B
C
D
E
Difficulty:
(N/A)
Question Stats:
0% (00:00) correct
100% (02:32) wrong based on 4 sessions
A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml of water is added into the vessel. If this operation is repeated another 2 times, what is the % of milk in the vessel at the end?. _________________
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
09 Oct 2011, 01:48
3
This post received KUDOS
maheshsrini wrote:
A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml of water is added into the vessel. If this operation is repeated another 2 times, what is the % of milk in the vessel at the end?.
You can solve these kind of questions with a standard formula..
If there is P volume of pure liquid initially and in each operation ,Q volume is take out and replaced by Q volume of water ,then at the end of n such operations ,the concentration (k) of the liquid in the solution is given by
{ (P-Q)/P }^n = k
This gives the concentration (k) of the liquid as a PROPORTION of the total volume of the solution. If concentration has to be expressed as percentage ,then it will be 100k.
Here , we have P= 300 ; Q = 30 and n =3(2+1)
{(300-30)/300}^3 = (9/10)^3 = 0.729
Therefore the percentage of the alcohol in the vessel is 72.9 % . _________________
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
09 Oct 2011, 09:09
gmatcracker24 seems like a big fan of alcohol. Its milk in here dude
gmatcracker24 wrote:
maheshsrini wrote:
A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml of water is added into the vessel. If this operation is repeated another 2 times, what is the % of milk in the vessel at the end?.
You can solve these kind of questions with a standard formula..
If there is P volume of pure liquid initially and in each operation ,Q volume is take out and replaced by Q volume of water ,then at the end of n such operations ,the concentration (k) of the liquid in the solution is given by
{ (P-Q)/P }^n = k
This gives the concentration (k) of the liquid as a PROPORTION of the total volume of the solution. If concentration has to be expressed as percentage ,then it will be 100k.
Here , we have P= 300 ; Q = 30 and n =3(2+1)
{(300-30)/300}^3 = (9/10)^3 = 0.729
Therefore the percentage of the alcohol in the vessel is 72.9 % .
_________________
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ MGMAT 6 650 (51,31) on 31/8/11 MGMAT 1 670 (48,33) on 04/9/11 MGMAT 2 670 (47,34) on 07/9/11 MGMAT 3 680 (47,35) on 18/9/11 GMAT Prep1 680 ( 50, 31) on 10/11/11
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
09 Oct 2011, 09:14
The formula { ( p-q)/p } ^n gives the %age of pure liquid left where q is volume of liquid taken out of p and replaced by another liquid (same quantity) n is the number of times this process is repeated.
eg in our case pure MILK = { (300-30)/300 }^3 * 300 = 729/1000 * 300 = 218.7 %age of pure milk is { (300-30)/300 }^3 = 72.9 % _________________
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ MGMAT 6 650 (51,31) on 31/8/11 MGMAT 1 670 (48,33) on 04/9/11 MGMAT 2 670 (47,34) on 07/9/11 MGMAT 3 680 (47,35) on 18/9/11 GMAT Prep1 680 ( 50, 31) on 10/11/11
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
09 Oct 2011, 09:16
catfreak wrote:
gmatcracker24 seems like a big fan of alcohol. Its milk in here dude
gmatcracker24 wrote:
maheshsrini wrote:
A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml of water is added into the vessel. If this operation is repeated another 2 times, what is the % of milk in the vessel at the end?.
You can solve these kind of questions with a standard formula..
If there is P volume of pure liquid initially and in each operation ,Q volume is take out and replaced by Q volume of water ,then at the end of n such operations ,the concentration (k) of the liquid in the solution is given by
{ (P-Q)/P }^n = k
This gives the concentration (k) of the liquid as a PROPORTION of the total volume of the solution. If concentration has to be expressed as percentage ,then it will be 100k.
Here , we have P= 300 ; Q = 30 and n =3(2+1)
{(300-30)/300}^3 = (9/10)^3 = 0.729
Therefore the percentage of the alcohol in the vessel is 72.9 % .
lol I am not a big fan of alcohol bro...neither fan of milk but unfortunately these kind of questions always have either alcohol or milk ...in it _________________
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
10 Oct 2011, 21:18
maheshsrini wrote:
But why is there a difference of 2.9% between the formula and the trial version?. Can somebody pls explain?
There should not be any difference between both.The difference is because in the trial versions they have removed the milk 30+30+30 which is not correct because after the first operation 30 litre of water is mixed to the solution ,and next operation onwards 30 litre removed contains water + milk. The approach should have been different.
The formula takes care of these conditions and hence accurate. _________________
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
10 Oct 2011, 22:38
I am not sure if the question is flawed or not. However, if we are NOT losing any solution after each operation the Final Solution should be 300 ml. In that case, I think, we must have 210 (300-90) ml Milk in the 300 ml Solution.
However, If we are taking out solution only to have 30 ml Milk: in the second operation we must take out 33.33 ml solution to have 30 ml of milk of which 3.33 ml will be water, because after the 1st operation 90% of the solution is Milk. Therefore, after the 2nd operation we will have 296.67 ml of solution. If we continue the process: after the 3rd operation we have 289.59 ml of the solution of which 210 ml is milk. The left over milk is 72.5%+ of the solution.
Here we are assuming that we must take out as much solution as to have 30 ml of milk. Hence, we are losing approximately 10.41 ml of the water.
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
12 Oct 2011, 20:42
Nice observation there.
Most of the solutions including mine assumes that we are removing 30ml solution and not 30ml Milk but the question says otherwise. Having said that, one can't just remove Milk from the mixture it has to be a solution ( with some water and milk in some %ages). Generally in such type of questions its the solution that is removed. So i think the question should clarify this more. Someone with better explanation, please clarify.
BDSunDevil wrote:
I am not sure if the question is flawed or not. However, if we are NOT losing any solution after each operation the Final Solution should be 300 ml. In that case, I think, we must have 210 (300-90) ml Milk in the 300 ml Solution.
However, If we are taking out solution only to have 30 ml Milk: in the second operation we must take out 33.33 ml solution to have 30 ml of milk of which 3.33 ml will be water, because after the 1st operation 90% of the solution is Milk. Therefore, after the 2nd operation we will have 296.67 ml of solution. If we continue the process: after the 3rd operation we have 289.59 ml of the solution of which 210 ml is milk. The left over milk is 72.5%+ of the solution.
Here we are assuming that we must take out as much solution as to have 30 ml of milk. Hence, we are losing approximately 10.41 ml of the water.
Can someone please verify?
_________________
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ MGMAT 6 650 (51,31) on 31/8/11 MGMAT 1 670 (48,33) on 04/9/11 MGMAT 2 670 (47,34) on 07/9/11 MGMAT 3 680 (47,35) on 18/9/11 GMAT Prep1 680 ( 50, 31) on 10/11/11
Re: A vessel has 300 ml of pure milk. 30 ml of milk is removed and 30 ml [#permalink]
18 Aug 2015, 23:34
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. _________________
As I’m halfway through my second year now, graduation is now rapidly approaching. I’ve neglected this blog in the last year, mainly because I felt I didn’...
Perhaps known best for its men’s basketball team – winners of five national championships, including last year’s – Duke University is also home to an elite full-time MBA...
Hilary Term has only started and we can feel the heat already. The two weeks have been packed with activities and submissions, giving a peek into what will follow...