Question

    The following questions contain three statements statement I, statement II and statement III. You have to determine which statement/s is/are necessary to answer the question and give an answer as.

    What is the speed of boat A in still water?

    >Statement I: Boat A takes 4 hours to travel 48 km downstream, while the speed of the current is 3 km/h. Statement II: Boat A takes 6 hours to travel 54 km upstream against the same current.               
    A Statement I alone is sufficient to answer the question Correct Answer Incorrect Answer
    B Statement II alone is sufficient to answer the question Correct Answer Incorrect Answer
    C Both statements together are necessary to answer the question Correct Answer Incorrect Answer
    D Either statement I alone or statement II alone is sufficient to answer the question Correct Answer Incorrect Answer
    E Both statements together are not sufficient to answer the question Correct Answer Incorrect Answer

    Solution

    Using Statement I, the downstream speed is 48 ÷ 4 = 12 km/h. With the current speed of 3 km/h, the speed of the boat in still water is 12 - 3 = 9 km/h. Using Statement II, the upstream speed is 54 ÷ 6 = 9 km/h. Adding the current speed of 3 km/h, the speed of the boat in still water is 9 + 3 = 12 km/h. The two statements together are necessary, as downstream and upstream speeds alone do not uniquely determine the speed of the boat in still water.

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