Question

    ‘A’ and ‘B’ can do a piece of work in 25 days

    and 30 days, respectively. If they started the work together and worked on it for 5 days, then find the time taken by ‘B’ alone to complete the remaining work.
    A 19 days Correct Answer Incorrect Answer
    B 15 days Correct Answer Incorrect Answer
    C 13 days Correct Answer Incorrect Answer
    D 20 days Correct Answer Incorrect Answer

    Solution

    Let total amount of work be 150 units (LCM of 25 and 30). Efficiency of ‘A’ = 150/25 = 6 units/day Efficiency of ‘B’ = 150/30 = 5 units/day Amount of work done by ‘A’ and ‘B’ together in 5 days = (6 + 5) × 5 = 55 units Time taken by B to complete remaining work = (150 – 55)/5 = 19 days

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