The probability of hitting a target by three marksmen are $\frac{1}{2},\,\frac{1}{3}$ and $\frac{1}{4}$ respectively. The probability that one and only one of them will hit the target when they fire simultaneously, is
$\frac{{11}}{{24}}$
$\frac{1}{{12}}$
$\frac{1}{8}$
None of these
Let $\Omega$ be the sample space and $A \subseteq \Omega$ be an event. Given below are two statements :
$(S1)$ : If $P ( A )=0$, then $A =\phi$
$( S 2)$ : If $P ( A )=$, then $A =\Omega$
Then
An unbiased die is tossed until a number greater than $4$ appears. The probability that an even number of tosses is needed is
A die is thrown. Describe the following events : $A$ : a number less than $7.$ Find the $A \cup B$.
Three coins are tossed once. Find the probability of getting atleast $2$ heads.
The probability of getting head and tail alternately in three throws of a coin (or a throw of three coins), is