Question

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

    upstream is 5:3. If the boat can travel 490 km in downstream in 5 hours, then find the time taken by the boat to cover 56 km in still water.
    A 39 minutes Correct Answer Incorrect Answer
    B 45 minutes Correct Answer Incorrect Answer
    C 75 minutes Correct Answer Incorrect Answer
    D 48 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 ‘5x’ km/h and ‘3x’ km/h, respectively. Speed of stream = 5x – 3x = 2x km/h Speed of boat in downstream = 5x + 2x = 7x km/h So, 7x = 490/5 => x = 14 Speed of boat in still water = 5 × 14 = 70 km/h Desired time = 56/70 x 60 = 48 minutes

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