Question

Three unbiased coins are tossed. What is the probability of getting at most 2 tails ?

• A. $\frac{1}{2}$
• B. $\frac{5}{8}$
• C. $\frac{7}{8}$
• D. $\frac{1}{4}$

Answer 1

The correct option is C $\frac{7}{8}$

Possible outcomes of tossing three coins are:
$\left(HHH\right),\left(HHT\right),\left(HTH\right),\left(THH\right),\left(TTT\right),\left(TTH\right),\left(THT\right),\left(HTT\right)$
where, $H$ and $T$ are represent "heads" and "tail".
Total no. of outcomes $=8$
No. of outcomes with at the most two tails $=7$
$\therefore$ Required probability $=$$\frac{7}{8}$
$\therefore$ Option C is correct.