Question

In a single throw of two coins, find the probability of getting
(i) both tails,
(ii) at least 1 tail,
(iii) at the most 1 tail.

Answer 1

The outcomes when two coins are tossed are HH, HT, TH and TT.
i.e., total no. of possible outcomes = 4

(i) Getting both tails means TT.
Number of outcomes with two tails = 1
∴ ${\mathrm{P}}_{\left(\mathrm{both}\mathrm{tails}\right)}=\frac{1}{4}$

(ii) Getting at least 1 tail means HT, TH and TT.
​With at least one tail, total number of outcomes = 3
∴ ${\mathrm{P}}_{\left(\mathrm{at}\mathrm{least}1\mathrm{tail}\right)}=\frac{3}{4}$

(iii) Getting at most 1 tail means HH, HT and TH.
The number of outcomes for at most 1 tail = 3
∴​${\mathrm{P}}_{\left(\mathrm{at}\mathrm{most}1\mathrm{tail}\right)}=\frac{3}{4}$