Question

Niech A,B ⊂ Ω. Oblicz P(A'∩B) , jeśli P(A')=1/4 i P(A'∩B')=1/7. Odpowiedz 3/28.

Answer 1

P(A'nB)=P(B)-P(AnB)
P(A'nB')=1-P(AuB)=1/7
P(AuB)=6/7
P(A)=1-1/4=3/4
P(AuB)=P(A)+P(B)-P(AnB)
P(A'nB)=P(AuB)-P(A)
P(A'nB)=6/7-3/4=24/28-21/28=3/28