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Math Help - [SOLVED] simple & complicated calcul

  1. #1
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    Smile [SOLVED] simple & complicated calcul

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  2. #2
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    Quote Originally Posted by jadee View Post
    Not sure.. :P just trying

    20% of group young people says it's old = false
    10% of old farts say their young = false

    34% of total group (young + old) says they are old = While their is a 30% false in that group. So you take away 30% of the false of the actual old group and u calculate the amount of students by distracting the actual old group from 5000.

    30% of 34% is 21%. 21% of 5000 = 1050 (actual old people) which leaves us 3950 students.
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  3. #3
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    okay but its nice to try!




    -- i've find 4300 lol --
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  4. #4
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    Quote Originally Posted by jadee View Post

    okay but its nice to try!




    -- i've find 4300 lol --
    I assume you got the right answer? How did you get to that?
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  5. #5
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    Quote Originally Posted by jadee View Post

    okay but its nice to try!




    -- i've find 4300 lol --
    I get 4000:

    Let x be the number of young people. Therefore there are 5000 - x old people. Therefore:

    (0.2)x + (0.9)(5000 - x) = (0.34)(5000).
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