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

    Question

    ‘A’ alone can complete a work in 40 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 66 days?
    A 45% Correct Answer Incorrect Answer
    B 55% Correct Answer Incorrect Answer
    C 65% Correct Answer Incorrect Answer
    D 50% Correct Answer Incorrect Answer
    E 60% Correct Answer Incorrect Answer

    Solution

    Let the total work = L.C.M of 40 and 30 = 120 units Then, efficiency of ‘A’ alone = 120 ÷ 40 = 3 units/day Combined efficiency of ‘A’ and ‘B’ = 120 ÷ 30 = 4 units/day So, efficiency of ‘B’ = 4 – 3 = 1 units/day So, work done by ‘B’ alone in 66 days = 1 × 66 = 66 units So, percentage of work completed by ‘B’ = (66 ÷ 120) × 100 = 55%

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