New RBI Grade B 2025 Notification will come Soon! Enroll Here

    Question

    The speed of a boat in still water is 5 times more than

    that of the current. If the boat takes 10 hours to cover 200 km upstream, then find the time taken by the boat to cover 420 km downstream.
    A 14 hours Correct Answer Incorrect Answer
    B 15 hours Correct Answer Incorrect Answer
    C 16 hours Correct Answer Incorrect Answer
    D 17 hours Correct Answer Incorrect Answer

    Solution

    Let the speed of the current be ‘x’ km/hr
    Therefore, speed of the boat in still water = 6x km/hr
    According to the question,
    6x – x = 200 / 10
    Or, 5x = 20
    Or, x = 4 km/hr
    Required time taken = 420 / (6x + x) = 420 / (7 × 4) = 420/28 = 15 hours

    Practice Next