MEDAL! ~PROBABLITY~

Alice and Bill are planning to have three children. (Assume it is equally likely for a boy or a girl to be born.)

What is the probability that all three will be the same gender?

Question

MEDAL! ~PROBABLITY~ 

Alice and Bill are planning to have three children. (Assume it is equally likely for a boy or a girl to be born.)

What is the probability that all three will be the same gender?

toasty_the_robot · Answer

1/3

anonymous · Answer

1/3

toasty_the_robot · Answer

well technically 1.5/3

anonymous · Answer

can someone explain to me why it would not be 1/8?

mathmate · Answer

For one child, probability is 1/2 for a boy.
For two boys, probability is (1/2)^2=1/4.
For three boys, probability is (1/2)^3=1/8 = P(BBB)
Assuming equality of probability between boys and girls, 
probability of three girls is also = 1/8 = P(GGG)
So probability of having 3 children of same gender = P(BBB)+P(GGG)

anonymous · Answer

so was i correct at 1/8? or no? hahaha

mathmate · Answer

Calculate P(BBB)+P(GGG) and you will find out.