Question

A die is thrown, then find the probability of the following events:
$A$ is an event: getting a number divisible by $3$.
$B$ is an event: getting a number less than $5$

Answer 1

A die is thrown,
Sample space, $S=\{1,2,3,4,5,6\}$
$\therefore n\left(S\right)=6$
$A$ is an event of getting a number divisible by $3$.
$\therefore A=\{3,6\}$
$n\left(A\right)=2$
$\therefore P\left(A\right)=\frac{n\left(A\right)}{n\left(S\right)}=\frac{2}{6}=\frac{1}{3}$
and $B$ is an event of getting a number less than $5$.
$\therefore B=\{1,2,3,4\}$
$n\left(B\right)=4$
$\therefore P\left(B\right)=\frac{n\left(B\right)}{n\left(S\right)}=\frac{4}{6}=\frac{2}{3}$