Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 month ago

How to Calculate the Time Taken To Run A 20m Race Using This Formula? ?

d(t) = -(10/t+0.625) + 20

I have to substitute D with this one as well but I found this one even more confusing?

Attachment image

8 Answers

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  • 1 month ago

    There are no units given in your formula. If the units are assumed to be metres then the formula does not make sense since 20m would have no solutions.

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  • D g
    Lv 7
    1 month ago

    d(t) is the distance at that time 

    The time will be t2 - t1

    d( t2) - d(t1) = 20m I'm assuming distance in meters

    Looking at the formula the distance formula is unusual

    The distance will only have a limit of 20 m at time = infinity

    This suggests the time of the race will be infinitely long

    You could start at a different distance which suggests z different time 

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  • 1 month ago

    Please check out if there is any error in the given formula first.

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  • ?
    Lv 7
    1 month ago

    Are you sure this formula is correct??

    Since d(t) = 20 m, according to the formula,

    ....................-10

    ..........20 = ------------- + 20 ⇒

    ....................t + 0.625

    ....................-10

    ..........0 = ------------- ⇒

    .................t + 0.625

    ..........0 = -10 which is INCONSISTENT

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  • 1 month ago

    let d(t) = 20m

    ..............10

    20 = - ------------- + 20

    ............t + 0.625

    20(t + 0.625) = - 10 + 20(t + 0.625)

    20t + 12.5 = - 10 + 20t + 12.5

    20t - 20t = 12.5 - 12.5 - 10

      0 = - 10

    Therefore there is no solution for this problem..

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  • 1 month ago

    Note, 1/2+3 does not mean the same as 1/(2+3).  To type out the equation correctly on a single line you need extra brackets:

    d(t) = -(10/t+0.625) + 20

    should be:

    d(t) = -(10/(t+0.625)) + 20

    Or even neater:

    d(t) = 20 – 10/(t+0.625)

    _________________________

    It’s a trick question.  The race can never be completed with this relationship between d and t.

    If you look at the equation:

    d(t) = 20 – 10/(t+0.625)

    you will see the right hand side is always less than 20, because you are subtracting 10/(t+0.625) from 20.

    It would take an infinite amount of time to move 20m.  When t equals infinity, 10/(t+0.625) equals zero.

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  • TomV
    Lv 7
    1 month ago

    Taking the image as the correct equation and substituting 20 for d(t), the equation has no finite solution.

    20 = -10/(t+0.625) + 20

    0 = -10/(t+0.625)

    0 = -10

    There is no finite value of t that satisfies the equation. Check your presentation of the problem for errors and resubmit.

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  • 1 month ago

    The text reads d(t) = -(10/t+0.625) + 20

    but the picture shows d(t) = -10/(t+0.625) + 20

    Which one is correct?

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