If $A$ and $B$ are arbitrary events,then

Fill in the blank in the following table:

$P(A)$	$P(B)$	$P(A \cap B)$	$P(A \cup B)$
$0.35$	$..........$	$0.25$	$0.6$

If the probability of $X$ to fail in the examination is $0.3$ and that for $Y$ is $0.2$,then the probability that either $X$ or $Y$ fail in the examination is

The probability of occurrence of an event $A$ is $1/2$ and that of $B$ is $3/10$. If $A$ and $B$ are mutually exclusive, then the probability of occurrence of neither $A$ nor $B$ is (in $/5$)

If $P(A) = 0.4$,$P(B) = x$,$P(A \cup B) = 0.7$ and the events $A$ and $B$ are mutually exclusive,then $x = $

If the probability of an event occurring is $3:8$,what is the probability of the event not occurring?