Question

    A can complete a work in 15 days, and B can complete the

    same work in 20 days. If they work together for 6 days, what fraction of the work is left?
    A 1/2 Correct Answer Incorrect Answer
    B 7/15 Correct Answer Incorrect Answer
    C 2/5 Correct Answer Incorrect Answer
    D 3/10 Correct Answer Incorrect Answer

    Solution

    Work done by A in 1 day = 1/15 Work done by B in 1 day = 1/20 Work done by A and B together in 1 day = (1/15 + 1/20) = 7/60 Work done in 6 days = 6 × 7/60 = 7/10 Fraction of work left = 1 - 7/10 = 3/10 Correct answer: d

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