Correct option is (b) 1/4
The possible events, when three coins are tossed, are
HHH, HTH, HHT, HTT, TTT, THT, TTH & THH.
The total number = 8 = probability space.
Clearly, HTH & THT are the favourable events.
The total = 2 = the number of favourable events.
∴ The probability, that head & tail show alternately,
\(= \frac{\text{Probability space}}{\text{The number of favourable events}}\)
\(= \frac 28\)
\(= \frac 14\)
