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    Question

    The speed ratio of a stream to the upstream speed of a

    boat is 1:9. A boat takes 2 hours and 30 minutes to travel 82.5 km downstream. Determine the time (in minutes) the boat will take to travel 54 km in still water.
    A 148 Correct Answer Incorrect Answer
    B 96 Correct Answer Incorrect Answer
    C 108 Correct Answer Incorrect Answer
    D 84 Correct Answer Incorrect Answer
    E 126 Correct Answer Incorrect Answer

    Solution

    Let the speed of boat in still water and speed of stream be 'v' and 'x' km/h respectively. ATQ, x:(v - x) = 1:9 Or, 9x = v - x Or, 'v' = 10x -------- (I) Downstream speed = v + x = 10x + x = '11x' km/h So, 11x = (82.5/2.5) Or, 11x = 33 So, 'x' = 3 On putting value of 'x' in equation (I) , We get, 'v' = 10 X 3 = 30 Therefore, required time = (54/30) = 1.8 hours = 1.8 X 60 = 108 minutes

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