New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    A and B together can complete a task in 12 days. B alone

    can complete it in 20 days. How long will it take A to complete the task if he works alone?
    A 30 days Correct Answer Incorrect Answer
    B 24 days Correct Answer Incorrect Answer
    C 40 days Correct Answer Incorrect Answer
    D 36 days Correct Answer Incorrect Answer

    Solution

    Let the total work be 1 unit of task. Work rate of A and B together = 1/12 units per day Work rate of B alone = 1/20 units per day Work rate of A alone = 1/12 − 1/20 = (5 − 3) / 60 = 2/60 = 1/30 units per day Therefore, A alone will complete the task in 30 days. Correct answer: a) 30 days

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