The probability of at least one of the events $A$ and $B$ occurring is $0.6$. If $A$ and $B$ occur simultaneously with probability $0.2$, then $P(\overline{A}) + P(\overline{B})$ is

$A, B, C$ are aiming to shoot a balloon. $A$ will succeed $4$ times out of $6$ attempts. The chance of $B$ to shoot the balloon is $3$ out of $5$ and that of $C$ is $2$ out of $3$. If the three aim to shoot the balloon simultaneously, then the probability that at least two of them hit the balloon is

If $A$ and $B$ are any two events,then the probability that exactly one of them occurs is

An experiment consists of recording the boy-girl composition of families with $2$ children. What is the sample space if we are interested in knowing whether it is a boy or girl in the order of their births?

$A$ bag contains $9$ discs of which $4$ are red,$3$ are blue,and $2$ are yellow. The discs are similar in shape and size. $A$ disc is drawn at random from the bag. Calculate the probability that it will be blue.

If two fair dice are rolled,then the probability that the sum of the numbers on the upper faces is at least $9$,is