Question

Three coins are tossed simultaneously. What is the probability that head and tail show alternately. (i.e., HTH or THT)?

• A. $\frac{3}{8}$
• B. $\frac{1}{4}$
• C. $\frac{1}{8}$
• D. $\frac{1}{2}$

Answer 1

The correct option is B $\frac{1}{4}$

The possible events, when three coins are tossed, are

$HHH,HTH,HHT,HTT,TTT,THT,TTH$ & $THH.$

The total number=8=probability space.

Clarly, HTH & THT are the favourable events.

The total=2=the number of favourable events.

$\therefore$ The probability, that head & tail show alternately,

=$\frac{probabilityspace}{thenumberoffavourableevents}=\frac{2}{8}=\frac{1}{4}$.