Maths Doubt

[neha 1]

Let X be the set of positive integers denoting the no. of tries it the cricket team to win the world cup. The team has equal odds for winning or losing any match . what is the prob. that they will in odd no. of matches?

[SINGHAM]

Neha, is the answer 2/3?

[Noel]

should be 2/3

[neha 1]

ya right answer is 2/3 ..please explain

[Noel]

Use geometric distribution,so P(X=n)=(1-p)^(n-1)*p
now probability of winning on an odd numbered match is 1/2+(1/2)^3+(1/2)^5+...
which is an infinite geometric series whose sum comes out to be 2/3

[Shefali]

Thanxx noel

[neha 1]

thanks:)