Question

    The speed of a boat in still water is 12.5 times the

    speed of the stream. If the difference between the upstream and downstream speed of the boats is 22 km/hr, then find the time taken by the boat to travel 253 km in upstream.
    A 5 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 lsquo;xrsquo; km/hr Therefore, speed of the boat in still water = 12.5x km/hr Upstream speed of the boat = 12.5x ndash; x = 11.5x km/hr Downstream speed of the boat = x + 12.5x = 13.5x km/hr According to the question, 13.5x ndash; 11.5x = 22 =gt; 2x = 22 =gt; x = 11 Therefore, upstream speed of the boat = 11.5x = 126.5 km/hr Required time taken = 253/126.5 = 2 hours

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