Three coins are tossed once. Find the probability of getting $2$ heads.

Two dice are thrown. The events $A, B$ and $C$ are as follows:
$A:$ getting an even number on the first die.
$B:$ getting an odd number on the first die.
$C:$ getting the sum of the numbers on the dice $\leq 5$.
Describe the events $B$ and $C$.

$A$ fair die is rolled once. Let $A$ be the event of getting an integer greater than $3$ and $B$ be the event of getting an integer less than $5$. Find $P(A \cup B)$.

If $A$ and $B$ are events of a random experiment such that $P(A \cup B) = \frac{4}{5}$,$P(\bar{A} \cup \bar{B}) = \frac{7}{10}$,and $P(B) = \frac{2}{5}$,then $P(A)$ equals

If a dice is thrown twice,then the probability of getting $1$ in the first throw only is

Three boxes contain respectively $3$ white and $1$ black,$2$ white and $2$ black,$1$ white and $3$ black balls. From each of the boxes,one ball is drawn at random. The probability that $2$ white and $1$ black balls will be drawn is: