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

    Question

    A man alone can do a work in 25 days. A woman can complete

    half of the same work in 20 days. In how many days can they complete 90% of the work together?
    A 14.32 days Correct Answer Incorrect Answer
    B 18.18 days Correct Answer Incorrect Answer
    C 16.67 days Correct Answer Incorrect Answer
    D 13.85 days Correct Answer Incorrect Answer

    Solution

    ATQ,

    Time taken by the woman to finish the entire work = 20 ÷ 0.5 = 40 days

    Let the total work be 200 units. {LCM of (25 and 40)}

    So, efficiency of the man = 200 ÷ 25 = 8 units/day

    And efficiency of the woman = 200 ÷ 40 = 5 units/day

    So, required time = (200 × 0.9) ÷ (8 + 5) = 13.85 days

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