Pipes and Cistern Problem Shortcut Tricks - Aptitude Test GMAT / GRE / CAT / Bank PO / SSC CGL
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Date: 2023-11-15
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Comments and reviews: 15
Markus
This assumes that the outflow is linear, in a real scenario the outflow would differe with time. So that when there were less water in the tank the outflow would be less as well.
Then to calculate the true time you would need to use integration for the different heights.
The equation you need for height is:
change in height = (Flowrate A+B) - area of opening C - sqrt(2-gravity -current height) / area of container.
Then integrate that equeation for height to get the time it take.
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This assumes that the outflow is linear, in a real scenario the outflow would differe with time. So that when there were less water in the tank the outflow would be less as well.
Then to calculate the true time you would need to use integration for the different heights.
The equation you need for height is:
change in height = (Flowrate A+B) - area of opening C - sqrt(2-gravity -current height) / area of container.
Then integrate that equeation for height to get the time it take.
reply
Marvin
First glance: IMPOSSIBLE to predict, as the rate of drain of C would depend on the water level, by some unknown ralationship.
If we apply the spherical cow technique and pretend A, B and C have constant rates (NOT stated in the problem) then:
V = total volume.
rateA = V/10
rateB = V/12
rateC = V/20
Solve for h(rateA + rateB - rateC) = V
The answer is independent of the size of V, so make it 1
h(1/10 + 1/12 - 1/20) = 1
h=7. 5 hours
reply
First glance: IMPOSSIBLE to predict, as the rate of drain of C would depend on the water level, by some unknown ralationship.
If we apply the spherical cow technique and pretend A, B and C have constant rates (NOT stated in the problem) then:
V = total volume.
rateA = V/10
rateB = V/12
rateC = V/20
Solve for h(rateA + rateB - rateC) = V
The answer is independent of the size of V, so make it 1
h(1/10 + 1/12 - 1/20) = 1
h=7. 5 hours
reply
dharshan
hey, u know one thing this sum, mean this kind was taught to me in my schl recently to say last yr wen i was in 8 std, so yes i did knew the ans. after the ques was asked i paused did in my rough, pad to specify, and got the ans exactly like the way u got it, yep the same exact kind of sum with same method was taught to me.
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hey, u know one thing this sum, mean this kind was taught to me in my schl recently to say last yr wen i was in 8 std, so yes i did knew the ans. after the ques was asked i paused did in my rough, pad to specify, and got the ans exactly like the way u got it, yep the same exact kind of sum with same method was taught to me.
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Madhav
Dear Ammar, your master's problem is mathematically wrong. In a Euclidean plane, we need at least 4 different lines to connect three pairs of colinear points without lifting the pen. In the case, of your logic, you are connecting three disks of sufficiently large size so that they can be connected using three lines.
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Dear Ammar, your master's problem is mathematically wrong. In a Euclidean plane, we need at least 4 different lines to connect three pairs of colinear points without lifting the pen. In the case, of your logic, you are connecting three disks of sufficiently large size so that they can be connected using three lines.
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Pranav
I got the answer by this way. Plz explain this way.
Pipe A x pipe B
10x12=120
120 hrs
In
Pipe A. will be fill = 120/10= 12 times
Pipe B. will be fill=120/12=10 times
Pipe C. Will be empty=120/20=6 times
Pipe A + pipe B - pipe C =
12+10-6=16
120/16= 7. 5
ie, 7. 5 hrs
reply
I got the answer by this way. Plz explain this way.
Pipe A x pipe B
10x12=120
120 hrs
In
Pipe A. will be fill = 120/10= 12 times
Pipe B. will be fill=120/12=10 times
Pipe C. Will be empty=120/20=6 times
Pipe A + pipe B - pipe C =
12+10-6=16
120/16= 7. 5
ie, 7. 5 hrs
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Izi
This solution is right only if we assume that pipe C empty the container with constant speed. We know that the speed varies with the height of the water content. Therefor the solution requires calculus involved.
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This solution is right only if we assume that pipe C empty the container with constant speed. We know that the speed varies with the height of the water content. Therefor the solution requires calculus involved.
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Muheni
Bro I may reply late to your vedio. But I have done with experiment about this kind of question but it so happen that the answer is always wrong with theoretical Approaches. So.
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Bro I may reply late to your vedio. But I have done with experiment about this kind of question but it so happen that the answer is always wrong with theoretical Approaches. So.
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Sapna
Nice class sir: ) I studied many topics from Vidya Guru sessions as well. I got many similar questions in my exams, which I had learnt in their videos.
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Nice class sir: ) I studied many topics from Vidya Guru sessions as well. I got many similar questions in my exams, which I had learnt in their videos.
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mikael
The only part you missed in the explanation was finding the common denominator to get to 2/15. Which is 120, then divide by 8. Good work though.
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The only part you missed in the explanation was finding the common denominator to get to 2/15. Which is 120, then divide by 8. Good work though.
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Ayushee
One of the few questions I could solve. BTW, this reminds me of my school days since, we used to solve this type of questions. Thanks for this!
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One of the few questions I could solve. BTW, this reminds me of my school days since, we used to solve this type of questions. Thanks for this!
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HARI
In above method is time consuming.
I have a simple idea to crack these questions.
Any one wants to know just ask me.
Best of luck
reply
In above method is time consuming.
I have a simple idea to crack these questions.
Any one wants to know just ask me.
Best of luck
reply
Rich
it does not matter if pipe c is opened at the same time as pipes a and b, it would be the same as if pipe c was already open.
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it does not matter if pipe c is opened at the same time as pipes a and b, it would be the same as if pipe c was already open.
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Shubham
but at last hour c outlet open and 1/20 part of container become empty. then it is not completely filled
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but at last hour c outlet open and 1/20 part of container become empty. then it is not completely filled
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Shaheed
I learnt this in my school. Now i used that trick. This is your 1st puzzle which i got right by myself.
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I learnt this in my school. Now i used that trick. This is your 1st puzzle which i got right by myself.
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Ameer
The answer is not correct u didn't notice & calculated outlet pipe and draining water. my answer is 11.
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The answer is not correct u didn't notice & calculated outlet pipe and draining water. my answer is 11.
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