Question

If a coin is tossed twice, find the probability of getting at least one head.

• A. $\frac{3}{4}$
• B. $\frac{2}{3}$
• C. $\frac{1}{2}$
• D. $\frac{1}{4}$

Answer 1

The correct option is A

$\frac{3}{4}$

Find the probability of getting a head
Sample space: $\mathrm{HH},\mathrm{HT},\mathrm{TH},\mathrm{TT}$

Probability =$\frac{\mathrm{Number}\mathrm{of}\mathrm{favourable}\mathrm{outcomes}}{\mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{outcomes}}$

The probability of getting no head is = $\frac{1}{4}$

$\therefore$Probability of getting at least one head = $1-\frac{1}{4}=\frac{3}{4}$

Hence, the probability of getting at least one head is $\frac{3}{4}$.