Question

    The distance between two stations is 1520 km. Train A

    takes 9 hours longer than Train B to cover this distance. If Train B travels 72 km/h faster than Train A, how much time does Train B take to cover the entire distance?
    A 10 hrs Correct Answer Incorrect Answer
    B 21 hrs Correct Answer Incorrect Answer
    C 18 hrs Correct Answer Incorrect Answer
    D 16 hrs Correct Answer Incorrect Answer

    Solution

    Let speed of train ‘A’ is ‘x’ km/h

    So, Speed of train ‘B’ = ‘x + 72’ km/h

    Let time taken by train ‘A’ to cover the whole distance is ‘t + 9’ hours

    So, time taken by train ‘B’ to cover the whole distance = ‘t’ hours

    So, x(t + 9) = (x + 72) × t

    Or, x = 8t

    And, x(t + 9) = 1520

    Or, 8t(t + 9) = 1520

    Or, t 2  + 9t – 190 = 0

    Or, (t + 19)(t – 10) = 0

    Or, t = 10

    So, time taken by train ‘B’ to cover the whole distance = 10 hours

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