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    Question

    Efficiency of A is 25% more than B and B takes 30 days

    to complete a piece of work. A started the work alone and then B joined him 4 days before actual completion of the work. For how many days A worked alone?
    A 75/13 days Correct Answer Incorrect Answer
    B 84/5 days Correct Answer Incorrect Answer
    C 95/8 days Correct Answer Incorrect Answer
    D 73/5 days Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Efficiency Ratio = A : B = 125 : 100 = 5 : 4 Days Ratio = A : B  = 4 : 5 B takes 30 days to complete a piece of work. => 5’s = 30 => 1’s = 6 => 6’s = 24 So A can complete the work in 24 days. Total units of work = 120 (LCM of 24,30) A = 5 unit B = 4 unit A and B worked for 4 days = 4 × (5+4) = 36 units Remaining work = 120 – 36 = 84 units Hence, A worked alone for = 84/5 days.

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