Question

    The speed of a boat in still water is 15 times the speed

    of the stream. If the difference between the upstream and downstream speed of the boats is 45 km/hr, then find the time taken by the boat to travel 1260 km in upstream.
    A 3 hours Correct Answer Incorrect Answer
    B 2 hours Correct Answer Incorrect Answer
    C 4 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 = 15x km/hr Upstream speed of the boat = 13x – x = 14x km/hr Downstream speed of the boat = x + 15x = 16x km/hr According to the question, 16x – 14x = 45 => 2x = 45 => x = 22.5 Therefore, upstream speed of the boat = 14x = 315 km/hr Required time taken = 1260/315 = 4 hours

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