... = P(AC) + P(BC) − P(ABC) nên P ( A + B + C ) = P(A) + P(B) + P(C) − P(AB) − P(AC) − P(BC) + P(ABC) Bài Cho P(A) = , P(B) = P(A + B) = Tính P(AB) , P(AB) , P(A + B) , P(AB) P(AB) Giải Do P(A ... P(A + B + C) = P(A) + P(B) + P(C) − P(AB) − P(AC) − P(BC) + P(ABC) Giải Ta có P ( A + B + C ) = P ( A + B ) + C = P(A + B) + P(C) − P [ (A + B)C] , P(A + B) = P(A) + P(B) − P(AB) , P [ (A ... = P(A) + P(B) − P(AB) , ta suy P(AB) = P(A) + P(B) − P(A + B) = 12 Do AB = A + B , nên ( ( ) ) P AB = P A + B = − P ( A + B ) = Tương tự, A + B = AB ta suy ( ) P A + B = − P ( AB ) = 11 12...