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

    Question

    ‘A’ alone can complete a work in 45 days while

    ‘A’ and ‘B’ together can complete the same work in 35 days. How much percentage of the work, ‘B’ alone can complete in 63 days?
    A 30% Correct Answer Incorrect Answer
    B 45% Correct Answer Incorrect Answer
    C 40% Correct Answer Incorrect Answer
    D 35% Correct Answer Incorrect Answer
    E 25% Correct Answer Incorrect Answer

    Solution

    Let the total work = L.C.M of 45 and 35 = 315 units Then, efficiency of ‘A’ alone = 315 ÷ 45 = 7 units/day Combined efficiency of ‘A’ and ‘B’ = 315 ÷ 35 = 9 units/day So, efficiency of ‘B’ = 9 – 7 = 2 units/day So, work done by ‘B’ alone in 63 days = 2 × 63 = 126 units So, percentage of work completed by ‘B’ = (126 ÷ 315) × 100 = 40%

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