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    Question

    ‘A’ alone can complete a work in 60 days while

    ‘A’ and ‘B’ together can complete the same work in 42 days. How much percentage of the work, ‘B’ alone can complete in 63 days?
    A 44% Correct Answer Incorrect Answer
    B 40% Correct Answer Incorrect Answer
    C 45% Correct Answer Incorrect Answer
    D 47% Correct Answer Incorrect Answer
    E 48% Correct Answer Incorrect Answer

    Solution

    Let the total work = L.C.M of 60 and 42 = 420 units Then, efficiency of ‘A’ alone = 420 ÷ 60 = 7 units/day Combined efficiency of ‘A’ and ‘B’ = 420 ÷ 42 = 10 units/day So, efficiency of ‘B’ = 10 – 7 = 3 units/day So, work done by ‘B’ alone in 63 days = 3× 63 = 189 units So, percentage of work completed by ‘B’ = (189 ÷ 420) × 100 = 45%

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