New SIDBI Grade A New Batch Starts on Nov 18

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    Question

    "A boat covers 66 km upstream and 98 km downstream in a total of 9 hours. Determine the time required for the boat to travel 48 km upstream and 112 km downstream, given that the boat's downstream speed is 40% higher than its speed in still water."

    A 12 hrs Correct Answer Incorrect Answer
    B 8 hrs Correct Answer Incorrect Answer
    C 15 hrs Correct Answer Incorrect Answer
    D 20 hrs Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Let, the speed of the boat in still water = 'p' km/h So, the downstream speed of the boat = 1.4p km/h Speed of the stream = 1.4p – p = 0.4p km/h Upstream speed of the boat = p – 0.4p = 0.6x km/h According to question: 66/0.6p + 98/1.4p = 9 110/p + 70/p = 9 p = 180/9, p = 20 So, the time taken by the boat to cover 48 km upstream and 112 km downstream = (48/12) + (112/28) = 4 + 4 = 8 hours

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