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

    Question

    The ratio of the speed of boat in upstream to speed of

    boat in downstream is 7:9. If the boat can cover a total of 35 km upstream and 108 km downstream in 17 hours, then find the time taken by the boat to cover 80 km in still water.
    A 12 hours Correct Answer Incorrect Answer
    B 9 hours Correct Answer Incorrect Answer
    C 10 hours Correct Answer Incorrect Answer
    D 14 hours Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let speed of boat in upstream and downstream be ‘7x’ km/h and ‘9x’ km/h respectively. 35/7x + 108/9x = 17 5/x + 12/x = 17 17 = 17x x = 1 Speed of boat in still water = (7x + 9x)/2 = 8x = 8 × 1 = 8 km/h Desired time = 80/8 = 10 hours

    Practice Next