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Homework Help: Propability and statistics

  1. Sep 16, 2010 #1
    1. The problem statement, all variables and given/known data
    Have the notebook in here but can't connect what's really happening AND very easy stuff ?
    for example :
    1) if A={a,b,c}
    A U B={a,b,c,d,e}
    A\B={a,b}
    B=?

    2) n(A)=12
    n(B)=10
    n(A U B)=18
    n(A\B)=?
    3)This one is tricky
    n(A)=4*n(B)
    n(A\B)=20
    A 'oposite of U' B= 16
    B\A=?

    2. Relevant equations



    3. The attempt at a solution
    1)?
    2) n(A U B)=n(A)+n(B)-n(A 'oposite of U' B)
    18 = 12+10-n(A 'oposite of U' B)
    n(A 'oposite of U' B)= 8 <------------- IS THIS CORRECT BECAUSE IF i DO IT MYSELF IT TURNS OUT 4 NOT 8 ,please confirm

    3) n(A)=4*n(B)
    24 why and how ?# 24 =4*n(B) /:4
    N(B)=6
    m(B\A)=2 <-------------AGAIN HOW CAN IT BE 2 ???????


    And also is there more info I can find in wikipedia about set theory if you know a link please send it to me. Thanks you
     
  2. jcsd
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