Question

Three coins are tossed, then what is the probability that at least two heads appears on upper face?

• A. $\frac{5}{8}$
• B. $40$
• C. $\frac{8}{5}$
• D. None of these

Answer 1

The correct option is D None of these

Here, $S=\{HHH,HTH,HHT,THH,HTT,THT,TTH,TTT\}$
and $E=\{HTH,HHT,THH,HHH\}$
$\therefore n\left(S\right)=8$
and $n\left(E\right)=4$
$\therefore$ Required probability $=\frac{n\left(E\right)}{n\left(S\right)}=\frac{4}{8}=\frac{1}{2}$