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Math Help - 300 mile race

  1. #1
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    300 mile race

    300 mi race. If you are 20 mi closer to the finish than the start are many miles have you traveled?

    The answer in the back of the book is: 160 mi. WHY?

    I tried figuring out and i cant
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  2. #2
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    S............a...............[you].......a-20.........F
    a + a-20 = 300
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  3. #3
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    Quote Originally Posted by yoman360 View Post
    300 mi race. If you are 20 mi closer to the finish than the start are many miles have you traveled?

    The answer in the back of the book is: 160 mi. WHY?

    I tried figuring out and i cant
    Didn't understand what you meant at first, I see you mean you are 20 mi closer to the finish line than you are to the start line.

    call your distance to start line x

    then your distance to finish line is 300-x

    we have 300-x = x-20

    that is, your (distance to finish line) equals (distance to start line) minus 20.

    solve for x.
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  4. #4
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    thanks I got 170 when i attempted it. I did this half 300=150 then 150 +20= 170 mi
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  5. #5
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    Quote Originally Posted by yoman360 View Post
    thanks I got 170 when i attempted it. I did this half 300=150 then 150 +20= 170 mi
    when you solve you get 2x=320 (or using Wilmer's letter 2a=320) and you calculate 320/2=160. You're doing things out of order.
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