Question

Three unbiased coins are tossed together. Find the probability of getting:
all heads

Answer 1

Elementary events associated to random experiment of tossing three coins are
HHH, HHT, HTH, THH, HTT, THT, TTH, TTT
$\therefore$ total number of elementary events = 8.
The event "Getting all heads" is said to occur, if the elementary event HHH occurs i.e. HHH is an outcome.
$\therefore$ Favourable number of elementary events = 1
Hence, required probability = $\frac{1}{8}$