Let $P(E)$ denote the probability of the occurrence of event $E$. If $P(A)= 0.5$ and $P(B)=1$ then the values of $P(A|B)$ and $P(B|A)$ respectively are
Here there is no dependency in event A and B.
So P(A $\cap$ B) = P(A) * P(B)
P(A/B)= probability of occurrence of event A when B has already occurred
= P(A $\cap$ B) / P(B)
= (0.5 * 1) /1 = 0.5
P(B/A)= probability of occurrence of event B when A has already occurred
= P(B $\cap$ A) / P(A)
= (1 * 0.5) / 0.5 = 1
X->YZ , Y->XZ , ...