Question

Two unbiased coins are tossed simultaneously. Find the probability of getting:
Two heads

Answer 1

If two unbiased coins are tossed simultaneously, we obtain any one of the following as an outcome.
$HH,HT,TH,TT$
$\Rightarrow$ Total number of elementary events, $n\left(S\right)=4$
Two heads are obtained if the elementary event $HH$ occurs.
$\Rightarrow$ Favourable number of elementary events, $n\left(E\right)=1$.

Probability of an event, $P\left(E\right)=\frac{n\left(E\right)}{n\left(S\right)}=\frac{1}{4}$
Hence, required probability is $\frac{1}{4}$.