📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!
  • google app store apple app store
    • ✖

      Question

      Pipes K and L alone can fill a tank in 4 hours and 6 hours

      respectively. When both pipes along with pipe M, an outlet pipe, are opened together, 3/4 of the tank gets filled in 120 minutes. Find the time taken by pipe M to empty a completely filled tank.
      A 18 hours Correct Answer Incorrect Answer
      B 20 hours Correct Answer Incorrect Answer
      C 22 hours Correct Answer Incorrect Answer
      D 24 hours Correct Answer Incorrect Answer
      E 26 hours Correct Answer Incorrect Answer

      Solution

      Let the total capacity of the tank be 12 litres.
      Efficiency of Pipe 'K' = 12 / 4 = 3 litres/hour
      Efficiency of Pipe 'L' = 12 / 6 = 2 litres/hour
      Let pipe 'M' empties the tank with an efficiency of 'm' litres/hour.
      Tank filled in 120 minutes = (3/4) × 12 = 9 litres
      ATQ,
      (3 + 2 - m) × (120/60) = 9
      (5 - m) × 2 = 9
      10 - 2m = 9
      2m = 1
      m = 0.5 litres/hour
      Time taken by M to empty the tank = 12 / 0.5 = 24 hours

      Practice Next
      More Pipes and cisterns Questions

      Relevant for Exams:

      ask-question