SETS

Posted November 18th, 2009 by alpha

If A and B are two sets having 3 elements in common. if n(A)=5, n(B)=4, find

$n[(A \times B) \cap (B \times A)]$

Comments

On November 19th, 2009 Structure says:

$(A\times B)\cap (C\times D)=(A\cap C)\times (B\cap D)$

$(A\times B)\cap (B\times A)=(A\cap B)\times (B\cap A)$

Answer is 9, like in 9math

On November 20th, 2009 alpha says:

:-))

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``Old theorems never die; they turn into definitions.''
----E. Hewitt

''ALPHA" =)