Question

Three unbiased coins are tossed. What is the probability of getting atleast $2$ heads

Answer 1

Here $S=\{TTT,TTH,THT,HTT,THH,HTH,HHT,HHH\}$.

Let $E=$ event of getting at least two heads $=\{THH,HTH,HHT,HHH\}$.

$P\left(E\right)=\frac{n\left(E\right)}{n\left(S\right)}$

$=\frac{4}{8}=\frac{1}{2}$