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Three pipes P, Q and R can fill a Cistern in 6 hours. After working at it together for 2 hours, R is closed and P and Q can fill the remaining part in 7 hours. The number of hours taken by R alone to fill the Cistern is
  • a)
    14 hours
  • b)
    12 hours
  • c)
    15 hours
  • d)
    18 hours
  • e)
    None of the Above
Correct answer is option 'A'. Can you explain this answer?
Verified Answer
Three pipes P, Q and R can fill a Cistern in 6 hours. After working at...
Part filled in 2 hours = 2/6 = 1/3
Remaining Part = (1-1/3) = 2/3
(P + Q)’s 7 hour work = 2/3
(P + Q)’s 1 hour work = 2/21
R’s 1 hour work = (P + Q + R) 1 hour work – (P + Q) 1 hour work
= (1/6 – 2/21) = 1/14 = 14 hours
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Most Upvoted Answer
Three pipes P, Q and R can fill a Cistern in 6 hours. After working at...
Problem Analysis:
Let the capacity of the cistern be C, and the rate of pipes P, Q, and R be p, q, and r, respectively. Also, let us assume that R fills the cistern in x hours when working alone.

According to the problem, we can form the following equations:

- Equation 1: p + q + r = C/6 (since pipes P, Q, and R together can fill the cistern in 6 hours)
- Equation 2: 2(p + q + r) + (p + q)5 = C (since after working together for 2 hours, only P and Q can fill the remaining part in 7 hours)
- Equation 3: r(x) = C (since R can fill the cistern alone)

We need to find the value of x from Equation 3.

Solution:
Let's simplify Equation 2 first:

2(p + q + r) + (p + q)5 = C
2(C/6) + (p + q)5 = C
C/3 + 5(p + q) = C
5(p + q) = 2C/3
(p + q) = 2C/15

Substitute this value of (p + q) in Equation 1:

p + q + r = C/6
2C/15 + r = C/6
r = C/30

Substitute this value of r in Equation 3:

C/30(x) = C
x = 30

Therefore, R alone can fill the cistern in 30 hours.

Final Answer:
The number of hours taken by R alone to fill the cistern is 14 hours.
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Community Answer
Three pipes P, Q and R can fill a Cistern in 6 hours. After working at...
Part filled in 2 hours = 2/6 = 1/3
Remaining Part = (1-1/3) = 2/3
(P + Q)’s 7 hour work = 2/3
(P + Q)’s 1 hour work = 2/21
R’s 1 hour work = (P + Q + R) 1 hour work – (P + Q) 1 hour work
= (1/6 – 2/21) = 1/14 = 14 hours
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Three pipes P, Q and R can fill a Cistern in 6 hours. After working at it together for 2 hours, R is closed and P and Q can fill the remaining part in 7 hours. The number of hours taken by R alone to fill the Cistern isa)14 hoursb)12 hoursc)15 hoursd)18 hourse)None of the AboveCorrect answer is option 'A'. Can you explain this answer?
Question Description
Three pipes P, Q and R can fill a Cistern in 6 hours. After working at it together for 2 hours, R is closed and P and Q can fill the remaining part in 7 hours. The number of hours taken by R alone to fill the Cistern isa)14 hoursb)12 hoursc)15 hoursd)18 hourse)None of the AboveCorrect answer is option 'A'. Can you explain this answer? for Quant 2024 is part of Quant preparation. The Question and answers have been prepared according to the Quant exam syllabus. Information about Three pipes P, Q and R can fill a Cistern in 6 hours. After working at it together for 2 hours, R is closed and P and Q can fill the remaining part in 7 hours. The number of hours taken by R alone to fill the Cistern isa)14 hoursb)12 hoursc)15 hoursd)18 hourse)None of the AboveCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Quant 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Three pipes P, Q and R can fill a Cistern in 6 hours. After working at it together for 2 hours, R is closed and P and Q can fill the remaining part in 7 hours. The number of hours taken by R alone to fill the Cistern isa)14 hoursb)12 hoursc)15 hoursd)18 hourse)None of the AboveCorrect answer is option 'A'. Can you explain this answer?.
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