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

    Question

    Time taken by a boat to travel certain distance in

    upstream direction is twice the time taken by the boat to cover same distance in downstream direction. If the total time needed to cover 24km upstream and 24km downstream is 3 hours, then calculate the average of speed of boat in still water and speed of stream.
    A 14 Correct Answer Incorrect Answer
    B 16 Correct Answer Incorrect Answer
    C 9 Correct Answer Incorrect Answer
    D 12 Correct Answer Incorrect Answer
    E None of the above Correct Answer Incorrect Answer

    Solution

    Let speed of boat in still water: u and speed of stream: v d/(u-v) = 2d/(u+v) => u = 3v 24/(u+v) + 24/(u-v) = 3 => v = 6km/hr Average of speed of still water and speed of stream = (u+v)/2 => 12

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