Question

    A and C together can paint a wall in 18 days. If C takes

    36 days to do it alone, and C works for 27 days after A leaves the job, what is the percentage of work completed by A?
    A 15.5% Correct Answer Incorrect Answer
    B 10.5% Correct Answer Incorrect Answer
    C 12.5% Correct Answer Incorrect Answer
    D 35.5% Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Given: A + C together can paint the wall in 18 days ⇒ Work rate = 1/18 C alone can do it in 36 days ⇒ Work rate = 1/36 C works for 27 days after A leaves Let A and C work together for x days Work by A + C = x × 1/18 Work by C alone = 27 × 1/36 = 3/4 Total work = 1 So, x/18 + 3/4 = 1 x/18 = 1 - 3/4 = 1/4 x = 1/4 × 18 = 4.5 days A's individual rate = 1/18 - 1/36 = 1/36 A’s work in 4.5 days = 4.5 × 1/36 = 1/8 Hence, A completed 1/8 = 12.5% of the work 

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