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Math Help - Average Speed

  1. #1
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    Average Speed

    If I drive x mph for t hours and then y mph for 2t hours, what is the expression for average speed?

    I know the average speed = distance/time but that's where I get stuck.
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  2. #2
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    Quote Originally Posted by magentarita View Post
    If I drive x mph for t hours and then y mph for 2t hours, what is the expression for average speed?

    I know the average speed = distance/time but that's where I get stuck.

    Hi . You will need to look for the total distance first .

    Use the formula s=vt (ie s=xt and s=y2t)

    average speed = (xt+y2t)/(2t+t)
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  3. #3
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    Quote Originally Posted by magentarita View Post
    If I drive x mph for t hours and then y mph for 2t hours, what is the expression for average speed?

    I know the average speed = distance/time but that's where I get stuck.
    d=x\times t+y \times 2t

    t=t+2t=3t

    \overline{v}=\frac{xt+2yt}{3t}

    CB
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  4. #4
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    Quote Originally Posted by magentarita View Post
    If I drive x mph for t hours and then y mph for 2t hours, what is the expression for average speed?

    I know the average speed = distance/time but that's where I get stuck.
    Find the distance covered when you drive x mph for t hours and y mph for 2t hours, then add them to get total distance

    EDIT : a minute late from CB and two minutes from mathaddict...
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  5. #5
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    Quote Originally Posted by magentarita View Post
    If I drive x mph for t hours and then y mph for 2t hours, what is the expression for average speed?

    I know the average speed = distance/time but that's where I get stuck.
    Or... d = rt.

    If you drive x mph for t hours, then the distance traveled is xt miles.
    If you drive y mph to 2t hours, then the distance traveled is 2yt miles.
    Total distance: xt + 2yt.
    Total time: t + 2t = 3t.

    Average speed:
    \frac{xt + 2yt}{3t} = \frac{x + 2y}{3}


    01


    Edit: beaten to it by three people!
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  6. #6
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    Quote Originally Posted by yeongil View Post
    Edit: beaten to it by three people!
    LOL !!
    even i'm surprised when i know you also give the answer
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  7. #7
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    Thanks..

    I want to thank all of you.
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