Question

    The speed of a boat in still water is 8 times the speed

    of the stream. If the difference between the upstream and downstream speed of the boats is 25 km/hr, then find the time taken by the boat to travel 175 km in upstream.
    A 5 hours Correct Answer Incorrect Answer
    B 2 hours Correct Answer Incorrect Answer
    C 1 hours Correct Answer Incorrect Answer
    D 6 hours Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the speed of the stream be ‘x’ km/hr Therefore, speed of the boat in still water = 8x km/hr Upstream speed of the boat = 8x – x = 7x km/hr Downstream speed of the boat = x + 8x = 9x km/hr According to the question, 9x – 7x = 25 => 2x = 25 => x = 12.5 Therefore, upstream speed of the boat = 7x = 87.5 km/hr Required time taken = 175/87.5 = 2 hours

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