An event $A$ is independent of itself if $P(A) = \dots$

Two dice are thrown independently. Let $A$ be the event that the number appeared on the $1^{\text{st}}$ die is less than the number appeared on the $2^{\text{nd}}$ die,$B$ be the event that the number appeared on the $1^{\text{st}}$ die is even and that on the $2^{\text{nd}}$ die is odd,and $C$ be the event that the number appeared on the $1^{\text{st}}$ die is odd and that on the $2^{\text{nd}}$ die is even. Then

Two dice are tossed. The probability that the total score is a prime number is

$A$ bag contains $3$ white and $5$ black balls. If one ball is drawn,then the probability that it is black,is

The probability that at least one of the events $A$ and $B$ occurs is $3/5$. If $A$ and $B$ occur simultaneously with probability $1/5$,then $P(A') + P(B')$ is (in $/5$)

$X$ speaks truth in $60\%$ and $Y$ in $50\%$ of the cases. The probability that they contradict each other in narrating the same incident is