If the odds in favour of an event be $3 : 5$,then the probability of non-occurrence of the event is

If the odds against an event be $2 : 3$,then the probability of its occurrence is

The probability that a leap year will have $53$ Fridays or $53$ Saturdays is

$A$ card is drawn at random from a well-shuffled deck of $52$ cards. What is the probability that the card is red or a queen?

In an entrance test that is graded on the basis of two examinations,the probability of a randomly chosen student passing the first examination is $0.8$ and the probability of passing the second examination is $0.7$. The probability of passing at least one of them is $0.95$. What is the probability of passing both?

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 $/5$)