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Math Help - Speed of Train

  1. #1
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    Speed of Train

    The trip from Manhattan to Montauk Point is 120 miles by train or by car. A train makes the trip in 2 hours, while a car makes the trip in
    5/2 hours. How much faster, in miles per hour, is the average speed of the train than the average speed of the car?

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  2. #2
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    Quote Originally Posted by magentarita View Post
    The trip from Manhattan to Montauk Point is 120 miles by train or by car. A train makes the trip in 2 hours, while a car makes the trip in
    5/2 hours. How much faster, in miles per hour, is the average speed of the train than the average speed of the car?

    The general formula is:

    average\ speed = \dfrac{complete\ distance}{elapsed\ time}

    Thus

    v_{train}=\dfrac{120\ mi}{2\ h}= 60 \dfrac{mi}h

    v_{car}=\dfrac{120\ mi}{\frac52\ h}= 48 \dfrac{mi}h

    Therefore the train is 12\ \frac{mi}h faster than the car.
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  3. #3
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    ok...

    Quote Originally Posted by earboth View Post
    The general formula is:

    average\ speed = \dfrac{complete\ distance}{elapsed\ time}

    Thus

    v_{train}=\dfrac{120\ mi}{2\ h}= 60 \dfrac{mi}h

    v_{car}=\dfrac{120\ mi}{\frac52\ h}= 48 \dfrac{mi}h

    Therefore the train is 12\ \frac{mi}h faster than the car.
    Nice set up and reply.
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