New Enroll in RBI Grade B New Batch - Starts on May 21

    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 Either statement I alone or statement II alone is sufficient to answer the question Correct Answer Incorrect Answer
    D Both statements together are necessary to answer the question Correct Answer Incorrect Answer
    E Both statements together are not sufficient to answer the question Correct Answer Incorrect Answer

    Solution

    Statement I alone: The downstream speed of the boat can be calculated as:

    Since downstream speed = B+C, where C=3 km/h: B+3=12 = B = 9 km/h Statement I alone is sufficient to find the speed of the boat in still water. Statement II alone: It states that the boat takes 6 hours to travel 54 km upstream but does not specify the speed of the current. Therefore, it is not possible to calculate the speed of the boat without knowing the current speed. Statement II alone is not sufficient. Combining both statements: Statement I already gives the speed of the current, and thus, using either statement independently (as long as we have the current speed from statement I) is sufficient. Hence, Only statement I alone is sufficient to answer the question.

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