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    Question

    ‘A’ alone can complete a work in 50 days while

    ‘A’ and ‘B’ together can complete the same work in 30 days. How much percentage of the work, ‘B’ alone can complete in 63 days?
    A 80% Correct Answer Incorrect Answer
    B 86% Correct Answer Incorrect Answer
    C 87% Correct Answer Incorrect Answer
    D 84% Correct Answer Incorrect Answer
    E 85% Correct Answer Incorrect Answer

    Solution

    Let the total work = L.C.M of 50 and 30 = 150 units Then, efficiency of ‘A’ alone = 150 ÷ 50 = 3 units/day Combined efficiency of ‘A’ and ‘B’ = 150 ÷ 30 = 5 units/day So, efficiency of ‘B’ = 5 – 3 = 2 units/day So, work done by ‘B’ alone in 63 days = 2 × 63 = 126 units So, percentage of work completed by ‘B’ = (126 ÷ 150) × 100 = 84%

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