Question

A and B toss a coin alternatively, the first to show a head being the winner. If A starts the game, the chance of his winning is?

• A. $5/8$
• B. $1/2$
• C. $1/3$
• D. $2/3$

Answer 1

The correct option is D $2/3$

For A to win outcomes can be H,TTH,TTTTH,...

=${1/2}^1+{1/2}^3+{1/2}^5+...$

=$=\frac{1/2}{1-1/4}=2/3$