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

    Question

    A’ and ‘B’ together can complete a

    work in 8 days, while ‘B’ and ‘C’ together can complete the work in 12 days. If ‘B’ takes 20 days to complete the work alone then find the time taken by all three together to complete 47.5% of work.
    A 3 days Correct Answer Incorrect Answer
    B 5 days Correct Answer Incorrect Answer
    C 6 days Correct Answer Incorrect Answer
    D 4 days Correct Answer Incorrect Answer
    E 7 days Correct Answer Incorrect Answer

    Solution

    Let the total work = 120 units Efficiency of (A + B) = 120/8 = 15 units/day Efficiency of (B + C) = 120/12 = 10 units/day Efficiency of ‘B’ = 120/20 = 6 units/day Efficiency of (A + B + C) = (15 + 10 – 6) = 19 units/day Required time taken = (0.475 × 120)/19 = 3 days

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