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

    Question

    ‘A’ alone can do some work in 25 days. ‘B’ and

    ‘C’ together can do the same work in 10 days. If ‘B’ is half as efficient as ‘A’, then find the time taken by ‘C’ to complete the work alone.
    A 12.5 days Correct Answer Incorrect Answer
    B 10.5 days Correct Answer Incorrect Answer
    C 11.5 days Correct Answer Incorrect Answer
    D 13.5 days Correct Answer Incorrect Answer

    Solution

    Let the total work be 50 units. {LCM (25 and 10)} So, efficiency of ‘A’ = (50/25) = 2 units/day So, efficiency of ‘B’ = (2 x 0.5) = 1 unit/day Efficiency of ‘B’ and ‘C’ together = (50/10) = 5 units/day So, efficiency of ‘C’ = 5 – 1 = 4 units/day So, time taken by ‘C’ to finish the work alone = (50/4) = 12.5 days

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