Question

    Speed of a boat in still water to speed of boat in

    upstream is 10: 9. If the boat can travel 220 km in downstream in 8 hours, then find the time taken by the boat to cover 25 km in still water.
    A 39 minutes Correct Answer Incorrect Answer
    B 51 minutes Correct Answer Incorrect Answer
    C 60 minutes Correct Answer Incorrect Answer
    D 75 minutes Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let speed of boat in still water and speed of boat in upstream be ‘10x’ km/h and ‘9x’ km/h, respectively. Speed of stream = 10x – 9x = x km/h Speed of boat in downstream = 10x + x = 11x km/h So, 11x = 220/8 => x = 2.5 Speed of boat in still water = 10 × 2.5 = 25 km/h Desired time = 25/25 x 60 = 60 minutes

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