Question

Daca stim card (A U B)=11,card (A-B)=2,card (B-A)=3,afla card A,card B si card (A n B).

Answer 1

card(A U B )=11 => A reunit cu B au 11 elemente
card(A-B) =2 => A are 2 elemente ce nu le are B
card(B-A) =3 => B are 3 elemente ce nu le are A
deci A are 2 elemente diferite de B si B are 3 elemente diferite de A=> A si B au 5 elemente unice... dar A si B au 11 in total => fiecare mai are inca 11-5=6 elemente ce se afla atat in A cat si in B =>
=> card (A) =2 +6 =8
card (B ) =3 +6 =9
 card (A n B )=6

Answer 2

card (A) =2 +6 =8 card (B ) =3 +6 =9 card (A n B )=6