$2$ boys and $2$ girls are in Room $X$, and $1$ boy and $3$ girls in Room $Y$. Specify the sample space for the experiment in which a room is selected and then a person.
Let us denote $2$ boys and $2$ girls in room $X$ as $B_{1}, \,B_{2}$ and $G_{1},$ and $G_{2}$ respectively. Let us denote $1$ boy and $3$ girls in room $Y$ as $B_{3},$ and $G_{3},\, G_{4}, \,G_{5}$ respectively.
Accordingly, the required sample space is given by
$S =\{X B_{1}, \,X B_{2},\, X G_{1},\, X G_{2}$, $Y B_{3},\, Y G_{3},\, Y G_{4}$, $Y G_{5}\}$
A bag contains $3$ red and $5$ black balls and a second bag contains $6$ red and $4$ black balls. A ball is drawn from each bag. The probability that one is red and other is black, is
A bag $x$ contains $3$ white balls and $2$ black balls and another bag $y$ contains $2$ white balls and $4$ black balls. A bag and a ball out of it are picked at random. The probability that the ball is white, is
A fair coin with $1$ marked on one face and $6$ on the other and a fair die are both tossed. find the probability that the sum of numbers that turn up is $12$.
A pair of a dice thrown, if $5$ appears on at least one of the dice, then the probability that the sum is $10$ or greater is
Three coins are tossed once. Find the probability of getting $3 $ heads