Question

    A boat can travel 28 km downstream in 30 min. The ratio

    of the speed of the boat in still water to the speed of the stream is 5: 3. How much time will the boat take to cover 30 km upstream?
    A 1(5/6) hr Correct Answer Incorrect Answer
    B 3(2/3) hr Correct Answer Incorrect Answer
    C 1(1/4) hr Correct Answer Incorrect Answer
    D 2(1/7) hr Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Speed of downstream = D/T = 28 × (60/30) = 56 km/hr The ratio of the speed of the boat in still water to the speed of the stream = 5: 3 (5x, 3x) => 8x = 56 => x = 7 Speed of upstream = 5x – 3x = 2x = 14 km/hr Distance = 30 km Time = D/S = 30/14 = 2(1/7) hr 

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