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    Question

    What is the speed of the stream?

    I. The boat covers a distance of 54 km in 3 hours while running downstream.

    II. The boat covers the same distance in 6 hours while running upstream.

    A If the question can be answered with the help of both the statements but not with the help of either statement itself Correct Answer Incorrect Answer
    B If the question cannot be answered even with the help of both the statements. Correct Answer Incorrect Answer
    C If the question can be answered with the help of statement II alone. Correct Answer Incorrect Answer
    D If the question can be answered with the help of statement I alone. Correct Answer Incorrect Answer
    E If the question can be answered with the help of either statement alone. Correct Answer Incorrect Answer

    Solution

    We know that speed = Distance/Time From statement I: Downstream speed = 54/3 = 18 km/hr Upstream speed = 54/6 = 9 km/hr Speed of stream = 1/2× (Downstream - upstream speed) => 1/2× (18 - 9) = 4.5 km/hr Therefore, both the statements are necessary to answer the question.

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