Question

    The following questions are accompanied by three statements I, II, and III. You have to determine which statements(s) is/are sufficient/necessary to answer the questions.

    What is the speed of stream? I   Sum of time

    taken by a boat in upstream and downstream is 46 hrs to cover distance 460 km in each.  II  Speed of boat in downstream is 50km/h.  III Boat cover 25 km in 2 hr, while rowing in upstream
    A Any two statements are sufficient to answer the question Correct Answer Incorrect Answer
    B Either I and II or II and III are sufficient to answer the question Correct Answer Incorrect Answer
    C Either I and II or I and III are sufficient to answer the question Correct Answer Incorrect Answer
    D Either I and III or II and III are sufficient to answer the question Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    From (I),  let the  Upstream Speed = x km/h,  Let the Downstream Speed = y km/h 460/x + 460/y = 46 1/x + 1/y = 1/10  From (II), we will get, y = 50, x = (50 × 10)/(50 – 10) = 12.5 km/h  From (III), we will get, x = 25/2 = 12.5 y = (12.5 × 10)/(12.5 – 10) = 50 km/h  Therefore Speed of Stream will be = (50 – 12.5)/2 = 18.75 km/h So, Any two statements are sufficient to answer the question

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