Class 7 Exam > Class 7 Questions > Two pipes A and B can fill a cistern in 37.5 ...
Start Learning for Free
Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if B is turned off after:
- a)5 min
- b)9 min
- c)10 min
- d)15 min
Correct answer is option 'B'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Verified Answer
Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes re...
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( 2/75 + 1/45) + (30 – x)2/75 = 1
⇒ 11x/225 + (60 – 2x)/75 = 1
⇒ 11x + 180 – 6x = 225
⇒ x = 9
Part filled by (A + B) in x min. + Part filled by
A in (30 – x) min. = 1.
∴ x( 2/75 + 1/45) + (30 – x)2/75 = 1
⇒ 11x/225 + (60 – 2x)/75 = 1
⇒ 11x + 180 – 6x = 225
⇒ x = 9
Most Upvoted Answer
Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes re...
Solution:
Let's assume the capacity of the cistern is 'x' liters.
Given, time taken by pipe A to fill the cistern = 37.5 minutes
So, in 1 minute, pipe A can fill = x/37.5 liters
Similarly, time taken by pipe B to fill the cistern = 45 minutes
So, in 1 minute, pipe B can fill = x/45 liters
Let's assume that pipe B is turned off after 't' minutes.
So, in the first 't' minutes, both pipes were open and the cistern was being filled.
Therefore, the amount of water filled in 't' minutes = (x/37.5 + x/45) * t
Now, we know that the cistern was filled in half an hour (i.e. 30 minutes)
So, the amount of water filled in 30 minutes = x
We need to find the value of 't' such that the amount of water filled in 't' minutes is half of the total capacity of the cistern.
Hence, we can write the equation as:
(x/37.5 + x/45) * t = x/2
Simplifying the above equation, we get:
t = 9 minutes
Therefore, pipe B should be turned off after 9 minutes in order to fill the cistern in half an hour. Hence, the correct answer is option 'B'.
Let's assume the capacity of the cistern is 'x' liters.
Given, time taken by pipe A to fill the cistern = 37.5 minutes
So, in 1 minute, pipe A can fill = x/37.5 liters
Similarly, time taken by pipe B to fill the cistern = 45 minutes
So, in 1 minute, pipe B can fill = x/45 liters
Let's assume that pipe B is turned off after 't' minutes.
So, in the first 't' minutes, both pipes were open and the cistern was being filled.
Therefore, the amount of water filled in 't' minutes = (x/37.5 + x/45) * t
Now, we know that the cistern was filled in half an hour (i.e. 30 minutes)
So, the amount of water filled in 30 minutes = x
We need to find the value of 't' such that the amount of water filled in 't' minutes is half of the total capacity of the cistern.
Hence, we can write the equation as:
(x/37.5 + x/45) * t = x/2
Simplifying the above equation, we get:
t = 9 minutes
Therefore, pipe B should be turned off after 9 minutes in order to fill the cistern in half an hour. Hence, the correct answer is option 'B'.
Attention Class 7 Students!
To make sure you are not studying endlessly, EduRev has designed Class 7 study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Class 7.
|
Explore Courses for Class 7 exam
|
|
Similar Class 7 Doubts
Top Courses for Class 7View all
Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer?
Question Description
Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? for Class 7 2024 is part of Class 7 preparation. The Question and answers have been prepared according to the Class 7 exam syllabus. Information about Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 7 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer?.
Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? for Class 7 2024 is part of Class 7 preparation. The Question and answers have been prepared according to the Class 7 exam syllabus. Information about Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 7 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer?.
Solutions for Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 7.
Download more important topics, notes, lectures and mock test series for Class 7 Exam by signing up for free.
Here you can find the meaning of Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Two pipes A and B can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will befilled in just half an hour, if B is turned off after:a)5 minb)9 minc)10 mind)15 minCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice Class 7 tests.
|
|
Explore Courses for Class 7 exam
|
|
Suggested Free Tests
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup