An experiment involves rolling a pair of dice and recording the numbers that come up. Describe the following events:
$A:$ the sum is greater than $8$,
$B : 2$ occurs on either die
$C:$ the sum is at least $ 7$ and a multiple of $3.$
Which pairs of these events are mutually exclusive ?
When a pair of dice is rolled, the sample space is given by
$S=\{(x, y): x$, $y=1,2,3,4,5,6\}$
$=\left\{\begin{array}{l}(1,1),(1,2),(1,3),(1,4),(1,5),(1,6) \\ (2,1),(2,2),(2,3),(2,4),(2,5),(2,6) \\ (3,1),(3,2),(3,3),(3,4),(3,5),(3,6) \\ (4,1),(4,2),(4,3),(4,4),(4,5),(4,6) \\ (5,1),(5,2),(5,3),(5,4),(5,5),(5,6) \\ (6,1),(6,2),(6,3),(6,4),(6,5),(6,6)\end{array}\right\}$
Accordingly,
$A=\{(3,6),(4,5),(4,6)$, $(5,4),(5,5),$ $(5,6)(6,3)$, $(6,4),(6,5),(6,6)\}$
$B =\{(2,1),(2,2),(2,3),$ $(2,4),(2,5),$ $(2,6)(1,2),(3,2)$, $(4,2),(5,2),(6,2)\}$
$C=\{(3,6),(4,5),(5,4),(6,3),(6,6)\}$
It is observed that $A \cap B=\phi$
$B \cap C=\phi$
$C \cap A=\{(3,6),(4,5)$, $(5,4),(6,3),(6,6)\}$ $ \neq \phi$
Hence, events $A$ and $B$ and events $B$ and $C$ are mutually exclusive.
The two events $A$ and $B$ have probabilities $0.25$ and $0.50$ respectively. The probability that both $A$ and $B$ occur simultaneously is $0.14$. Then the probability that neither $A$ nor $B$ occurs is
Let $\mathrm{X}$ and $\mathrm{Y}$ be two events such that $\mathrm{P}(\mathrm{X})=\frac{1}{3}, \mathrm{P}(\mathrm{X} \mid \mathrm{Y})=\frac{1}{2}$ and $\mathrm{P}(\mathrm{Y} \mid \mathrm{X})=\frac{2}{5}$. Then
$[A]$ $\mathrm{P}\left(\mathrm{X}^{\prime} \mid \mathrm{Y}\right)=\frac{1}{2}$ $[B]$ $\mathrm{P}(\mathrm{X} \cap \mathrm{Y})=\frac{1}{5}$ $[C]$ $\mathrm{P}(\mathrm{X} \cup \mathrm{Y})=\frac{2}{5}$ $[D]$ $\mathrm{P}(\mathrm{Y})=\frac{4}{15}$
An experiment consists of rolling a die and then tossing a coin if the number on the die is even. If the number on the die is odd, the coin is tossed twice. Write the sample space for this experiment.
The probability that a marksman will hit a target is given as $1/5$. Then his probability of at least one hit in $10$ shots, is
Three coins are tossed once. Let $A$ denote the event ' three heads show ', $B$ denote the event ' two heads and one tail show ' , $C$ denote the event ' three tails show and $D$ denote the event 'a head shows on the first coin '. Which events are simple ?