If $A$ and $B$ are two mutually exclusive events,then $P(A \cup B) = $

If $A$ and $B$ are mutually exclusive events,then the value of $P(A \cup B)$ is

Three critics review a book. For the three critics,the odds in favour of the book are $(5: 2)$,$(4: 3)$ and $(3: 4)$ respectively. The probability that the majority is in favour of the book is

It is $5:2$ against a husband who is $65$ years old living till he is $85$ and $4:3$ against his wife who is now $58$,living till she is $78$. If the probability that at least one of them will be alive for $20$ years is $k$,then the value of $49k$ is:

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

There are $100$ lottery tickets numbered from $1$ to $100$. If a ticket is drawn at random,find the probability that the number on it is a multiple of $3$ or $5$.