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    Question

    A robot can finish a task as quickly as two humans, 'E'

    and 'F', together. If human 'E' can finish the task in 8 hours and human 'F' in 24 hours, how long will it take for the robot to complete the task?
    A 8 hrs Correct Answer Incorrect Answer
    B 7 hrs Correct Answer Incorrect Answer
    C 6 hrs Correct Answer Incorrect Answer
    D 5 hrs Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Total work = 24 units (LCM of 8 and 24) Efficiency of human 'E' = 24/8 = 3 units/hour Efficiency of human 'F' = 24/24 = 1 unit/hour Time taken by humans 'E' and 'F' to complete the work together = 24/(3 + 1) = 6 hours Time taken by the robot = 6 hours

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