Question

Two unbiased coins are tossed simultaneously. Find the probability of getting:
at least one head

Answer 1

If two unbiased coins are tossed simultaneously we obtain any one of the following as an outcome.HH, HT, TH, TT.$\therefore$ Total number of elementary events = 4
At least one head is obtained if any one of the following elementary events happens:
HH, HT, TH.
$\therefore$ Favourable of elementary events = 3.
Hence, required probability = $\frac{3}{4}$.