Question

    P can do a piece of work in 30 days. Q do the same work in 40 days. R can do it in 35 days. P and R worked for 4 days and handed it to Q. Q worked for some days and handed it again to P and R 6 days before completing the work. For how many days did Q work? 

    A 15 (5/21) days Correct Answer Incorrect Answer
    B 10 days Correct Answer Incorrect Answer
    C 25 days Correct Answer Incorrect Answer
    D 5 days Correct Answer Incorrect Answer

    Solution

    L.C.M of 30, 40 and 35 days = 840 days P can do 840/30 = 28 units/day Q can do 840/40 = 21 units/day R can do 840/35 = 24 units/day Now, in (4 + 6) days (P + R) can do = 10 × 52 = 520 units Therefore, Remaining unit work done by Q = 840 – 520 = 320 Therefore, Q’s work for (320/21) = 15(5/12)days  

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