Question

If a coin is tossed 3 times, what is the probability of getting atleast one tail?

• A. $\frac{1}{8}$
• B. $\frac{7}{8}$
• C. $\frac{1}{4}$
• D. $\frac{1}{16}$

Answer 1

The correct option is B

$\frac{7}{8}$

Given, a coin is tossed 3 times.

Total possible outcomes = {HHH, HHT, HTT, HTH, THH, TTH, THT, TTT} (where H = Heads, T= Tails)

= 8

Number of favourable outcomes (getting at least one tail) = {HHT, HTT, HTH, THH, TTH, THT, TTT}

Out of 8 possible outcomes, there are 7 favourable outcomes.

We have,

Probability of an event, P(E) = $\frac{\text{number of favourable outcomes}}{\text{total number of outcomes}}$

$\Rightarrow$ P (getting atleast one tail) = $\frac{7}{8}$

Therefore, the probability of getting atleast one tail is $\frac{7}{8}$ .