- Home
- Standard 11
- Mathematics
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 $\leq 5$
State true or false $:$ (give reason for your answer)
Statement : $A^{\prime}$, $B^{\prime}, C$ are mutually exclusive and exhaustive.
Solution
$A=\left\{\begin{array}{l}(2,1),(2,2),(2,3),(2,4),(2,5),(2,6),(4,1),(4,2),(4,3) \\ (4,4),(4,5),(4,6),(6,1),(6,2),(6,3),(6,4),(6,5),(6,6)\end{array}\right\}$
$B=\left\{\begin{array}{l}(1,1),(1,2),(1,3),(1,4),(1,5),(1,6),(3,1),(3,2),(3,3), \\ (3,4),(3,5),(3,6),(5,1),(5,2),(5,3),(5,4),(5,5),(5,6)\end{array}\right\}$
$C=\{(1,1),(1,2),(1,3),(1,4),(2,1),(2,2),(2,3),(3,1),(3,2),(4,1)\}$
It is observed that $A^{\prime} \cup B^{\prime} \cup C=S$.
However,
$B^{\prime} \cap C=\{(2,1),(2,2),(2,3),(4,1)\} \neq \phi$
Therefore, events $A^{\prime}, \,B^{\prime}$ and $C$ are not mutually exclusive and exhaustive.
Thus, the given statement is false.
