Question

    Working alone, B can complete the work in 25 days. C is

    twice as efficient as B and A takes 2.5 days more than it takes C to complete the work. Working together, in how much time would they be able to complete 14 such works?
    A 70 days Correct Answer Incorrect Answer
    B 48 days Correct Answer Incorrect Answer
    C 87 days Correct Answer Incorrect Answer
    D 63 days Correct Answer Incorrect Answer
    E 75 days Correct Answer Incorrect Answer

    Solution

    Time taken by B to complete the work = 25 days
    Time taken by C to complete the work = 25/2 = 12.5 days
    Time taken by A to complete the work alone = 12.5 + 2.5 = 15 days
    Work done by A, B and C together in 1 day.
    ⇒ (1/25 + 1/12.5 + 1/15) = (12 + 24 + 20)/300 = 56/300
    this means if would take 300/56 days for A, B and C to complete the work together
    ∴ Time taken A, B and C to complete 14 works = 14 × 300/56 days = 75 days

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