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

    Question

    ‘A’ takes 20 days to do some work. If ‘B’ is 20%

    more efficient than ‘A’, then find the time taken by them to finish 99% of the work together.
    A 9 days Correct Answer Incorrect Answer
    B 4 days Correct Answer Incorrect Answer
    C 6 days Correct Answer Incorrect Answer
    D 12 days Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the work by 100x units.
    Efficiency of ‘A’ = 100x ÷ 20 = ‘5x’ units/day
    Efficiency of ‘B’ = 5x × 1.2 = ‘6x’ units/day
    99% of the work = 100x × 0.99 = 99x units
    Required time = 99x ÷ (5x + 6x) = 9 days.

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