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

    Question

    'A' and 'B' together build a wall in 48 days. If 'A'

    builds the wall in 120 days, then find the time taken by 'B' to build the wall.
    A 72 days Correct Answer Incorrect Answer
    B 80 days Correct Answer Incorrect Answer
    C 60 days Correct Answer Incorrect Answer
    D None of these Correct Answer Incorrect Answer

    Solution

    Let the total work be 240 units (LCM of 48 and 120)Combined efficiency of 'A' and 'B' = (240/48) = 5 units/dayEfficiency of 'A' = (240/120) = 2 units/daySo, efficiency of 'B' = 5 - 2 = 3 units/dayTherefore, required time = (240/3) = 80 days

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