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

    Question

    The speed of a boat in still water is 7.5 times the

    speed of the stream. If the difference between the upstream and downstream speed of the boats is 40 km/hr, then find the time taken by the boat to travel 260 km in upstream.
    A 5 hours Correct Answer Incorrect Answer
    B 2 hours Correct Answer Incorrect Answer
    C 9 hours Correct Answer Incorrect Answer
    D 6 hours Correct Answer Incorrect Answer

    Solution

    Let the speed of the stream be ‘x’ km/hr Therefore, speed of the boat in still water = 7.5x km/hr Upstream speed of the boat = 7.5x – x = 6.5x km/hr Downstream speed of the boat = x + 7.5x = 8.5x km/hr According to the question, 8.5x – 6.5x = 40 => 2x = 40 => x = 20 Therefore, upstream speed of the boat = 6.5x = 130 km/hr Required time taken = 260/130 = 2 hours

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