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

    Question

    'A' and 'B' can together complete a job in 15 days. If

    'B' alone can finish 50% of the job in 20 days, how long would it take 'A' alone to complete the entire job?
    A 10 days Correct Answer Incorrect Answer
    B 12 days Correct Answer Incorrect Answer
    C 24 days Correct Answer Incorrect Answer
    D 18 days Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    ATQ, Time taken by 'B' to complete the job alone = 20 × (100/45 ) = 40 days. Let the total work be 120 units. {LCM of 15 and 40}. Efficiency of 'A' and 'B' together = (120/15) =8 units/day. Efficiency of 'B' = (120/40) = 3 units/day. Efficiency of 'A' = 8−3 = 5 units/day. Time taken by 'A' to complete the work alone = (120/5) = 24 days.

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