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

    Question

    The speed of a boat in still water is 28 km/hr. If the

    boat covers 140 km in upstream in 7 hours, then find the time taken by the boat to travel 180 km in downstream.
    A 5 hours Correct Answer Incorrect Answer
    B 4 hours Correct Answer Incorrect Answer
    C 3.5 hours Correct Answer Incorrect Answer
    D 5.5 hours Correct Answer Incorrect Answer

    Solution

    Let the speed of the boat in still water and the speed of the current be ‘x’ km/hr and ‘y’ km/hr, respectively Upstream speed of the boat = (x – y) = 140/7 = 20 km/hr Or, 28 – y = 20 Or, y = 28 – 20 = 8 km/hr Therefore, downstream speed of the boat = 28 + 8 = 36 km/hr Required time taken = 180/36 = 5 hours

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