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

    Question

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

    upstream is 12:7. If the boat can travel 340 km in downstream in 5 hours, then find the time taken by the boat to cover 16 km in still water.
    A 30 minutes Correct Answer Incorrect Answer
    B 20 minutes Correct Answer Incorrect Answer
    C 15 minutes Correct Answer Incorrect Answer
    D 18 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 ‘12x’ km/h and ‘7x’ km/h, respectively. Speed of stream = 12x – 7x = 5x km/h Speed of boat in downstream = 12x + 5x = 17x km/h So, 17x = 340/5 = 68 Or, x = 4 Speed of boat in still water = 12 × 4 = 48 km/h Desired time = 16/48 = 20 minutes

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