(adsbygoogle = window.adsbygoogle || []).push({}); 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

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# Homework Help: Propability and statistics

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