Question

Two unbiased coins are tossed at a time, find the probability of getting at least one head.

• A. $\frac{1}{4}$
• B. $\frac{1}{2}$
• C. $\frac{3}{4}$
• D. None

Answer 1

The correct option is C $\frac{3}{4}$

When two unbiased coins are tossed then

Total no . of outcomes,n(S)=$2\times 2=4\left[\right(H,H),(T,T),(H,T),(T,H\left)\right]$

The favorable outcomes=$(H,H),(H,T),(T,H)$

$\Rightarrow$Then no. of favorable outcomes,n(E)=3

$\therefore Probability\left(P\right)=\frac{n\left(E\right)}{n\left(S\right)}=\frac{3}{4}$