Question

    A and B can do a work together in 10 days. B and C can

    do the same work in 15 days, how many days will B take to complete the work if A, B and C together can do the same work in 7.5 days?
    A 15 days Correct Answer Incorrect Answer
    B 30 days Correct Answer Incorrect Answer
    C 25 days Correct Answer Incorrect Answer
    D 28 days Correct Answer Incorrect Answer

    Solution

    Let the work done by B in one day be 1/x A + B = 1/10, B + C = 1/15. Adding both the above equation- A+2B+C = 5/30 = 1/6 Also, A + B + C = 1/7.5 Total work done by B = 1/6 – 1/7.5 = 1/30 Therefore, time taken by B = 30 days. Answer: b) 30 days.

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