Question

According to the general equation for conditional probability, if P(AuB')=5/9 and P(B)=1/3, what is P(A|B')?

Answer 1

$P(B)=\frac{1}{3}$
$P(B')=1-\frac{1}{3}=\frac{2}{3}$
$P(A|B')=\frac{P(A\cap B')}{P(B')}=\frac{\frac{5}{9}}{\frac{2}{3}}=\frac{5}{6}$
The correct answer choice is C.