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    Question

    The distance covered by a train in (4y-1) hours are

    (64y3-1) km. The speed of the train is. 
    A 12y² + 2y - 2) Correct Answer Incorrect Answer
    B 16y² + 4y + 1 Correct Answer Incorrect Answer
    C 16y² + 2y + 1) Correct Answer Incorrect Answer
    D 12y² + 3y + 1) Correct Answer Incorrect Answer

    Solution

    a³-b³ = (a - b) (a² + ab + b²) The speed of the train =(64y3-1) /(4y-1) =(4y)3-1/ (4y-1) =(4y-1) (16y2+4y+1)/ (4y-1) = (16y² + 4y + 1) km/h The speed of the train is (16y² + 4y + 1) km/h.

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