New RBI Grade B 2025 Notification will come Soon! Enroll Here

    Question

    Pipe ‘X’ and pipe ‘Y’ can fill a tank in 30

    hours and 45 hours respectively. Pipe ‘Z’ is 20% more efficient than pipe ‘X’. If pipe ‘Y’ and pipe ‘Z’ are turned on together for 10 hours, how long will pipe ‘X’ take to fill the rest of the tank alone?
    A 18.44 hrs Correct Answer Incorrect Answer
    B 11.33 hrs Correct Answer Incorrect Answer
    C 17.77 hrs Correct Answer Incorrect Answer
    D 11.11 hrs Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ,

    Let total capacity of the tank be 180 units {LCM of (30 and 45)} Efficiency of pipe ‘X’ = 180 ÷ 30 = 6 units/hour Efficiency of pipe ‘Y’ = 180 ÷ 45 = 4 units/hour Efficiency of pipe ‘Z’ = 1.20 × 6 = 7.2 units/hour Water filled by pipe ‘Y’ and pipe ‘Z’ in 10 hours = (4 + 7.2) × 10 = 112 units Remaining water to be filled = 180 – 112 = 68 units Time taken by pipe ‘X’ to fill remaining tank = 68 ÷ 6 = 11.33 hours

    Practice Next

    Relevant for Exams: