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    Question

    A and B together can complete a piece of work in 10

    days. A alone can complete the work in 15 days. How many days will B take to complete the work alone?
    A 30 days Correct Answer Incorrect Answer
    B 20 days Correct Answer Incorrect Answer
    C 25 days Correct Answer Incorrect Answer
    D 40 days Correct Answer Incorrect Answer

    Solution

    Let the total work be 1 unit. A’s efficiency = 1/15 (work per day). A and B together = 1/10 (work per day). B's efficiency = (1/10) - (1/15) = (3 - 2)/30 = 1/30 (work per day). Thus, B alone can complete the work in 30 days.

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