Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 4)
4.
Two pipes A and B can fill a cistern in 37
minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the B is turned off after:
minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the B is turned off after:
Answer: Option
Explanation:
Let B be turned off after x minutes. Then,
Part filled by (A + B) in x min. + Part filled by A in (30 -x) min. = 1.
 x |
 |
2 | + | 1 |  |
+ (30 - x). | 2 | = 1 |
| 75 | 45 | 75 |
 |
11x | + | (60 -2x) | = 1 |
| 225 | 75 |
11x + 180 - 6x = 225.
x = 9.
Discussion:
90 comments Page 4 of 9.
Silvi said:
1 decade ago
This is not logical reasoning. By multiplying them with minutes, you can not estimates their unit to be a part.
Hence, the "=1" here is unaccepted. You must provide with minutes unit too.
Hence, the "=1" here is unaccepted. You must provide with minutes unit too.
Abhishek said:
1 decade ago
@Rohit are you kidding bro?
If A and B take more than 4 hours to fill the tank (they takes 6 and 8 hours). Then how could anyone of them fill it in 4 hours. Use some mind.
If A and B take more than 4 hours to fill the tank (they takes 6 and 8 hours). Then how could anyone of them fill it in 4 hours. Use some mind.
Arun said:
5 years ago
Let 'B' be turned off after 'x' minutes.
Then:
Part filled by A and B in 1 minute:
[(2/75) + (1/x) ] = [1/30] minutes.
[(2x + 75) ] 30 = 75x.
x = 225/9 = 9 minutes(Ans).
Then:
Part filled by A and B in 1 minute:
[(2/75) + (1/x) ] = [1/30] minutes.
[(2x + 75) ] 30 = 75x.
x = 225/9 = 9 minutes(Ans).
Kunal Aryan said:
9 years ago
For this type of question use Short Trick :
[Y*(1 - t / x)]
Here X= 75/2 ; Y=45 and t= 30mint. (ie. half an hour).
Soln: 45*(1 - 30 * 2 / 75) = 9 mints. answer.
[Y*(1 - t / x)]
Here X= 75/2 ; Y=45 and t= 30mint. (ie. half an hour).
Soln: 45*(1 - 30 * 2 / 75) = 9 mints. answer.
Pintu Francis said:
1 decade ago
Y going complicated? be simple.
A work in 1 min 2/75.
B work in 1 min 1/45.
So,
(2/75) 30+ (1/45) x=1.
Since A work for 30 min and B for x min.
Solving X=9.
A work in 1 min 2/75.
B work in 1 min 1/45.
So,
(2/75) 30+ (1/45) x=1.
Since A work for 30 min and B for x min.
Solving X=9.
Madhubala said:
8 years ago
For 1min it takes( 2/75).
For 30 min (1/2 hour) it takes 2/75*30=4/5 part.
So remaining only 1 part out of 5 which is going to fill by B.
So (1/5*45) = 9 min.
For 30 min (1/2 hour) it takes 2/75*30=4/5 part.
So remaining only 1 part out of 5 which is going to fill by B.
So (1/5*45) = 9 min.
Clinton said:
5 years ago
((A - Time of closing)/A) * B = Answer.
Here,
A=75/2.
Time of Closing the pipe=30.
B = 45.
So, Apply in the formula.
(((75/2)-30)/(75/2)) * 45 = 9 (Answer).
Here,
A=75/2.
Time of Closing the pipe=30.
B = 45.
So, Apply in the formula.
(((75/2)-30)/(75/2)) * 45 = 9 (Answer).
(2)
Nilesh12 said:
6 years ago
Formula(1 - total time/2nd pipe time)*1st pipe time.
then,
(1-30/75/2)*45.
Means,
(1-60/75)*45.
(75-60/75)*45.
(1/5)*45.
Answer 9.
then,
(1-30/75/2)*45.
Means,
(1-60/75)*45.
(75-60/75)*45.
(1/5)*45.
Answer 9.
(1)
Azharudhin said:
9 years ago
Hi @Meraj Husain, please explain how 60 came?
Your explanation is nice, please explain clearly once again. Thank you for your comments.
Your explanation is nice, please explain clearly once again. Thank you for your comments.
NAZMUL HASAN APU said:
4 years ago
A's work in 1 hour = 2/75.
A's work in 30 minutes = (2/75) * 30 = 4/5.
Remaining work (1- 4/5) = 1/5.
B's work = (1/5) * 45 = 9 min.
A's work in 30 minutes = (2/75) * 30 = 4/5.
Remaining work (1- 4/5) = 1/5.
B's work = (1/5) * 45 = 9 min.
(117)
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