A man visits a couple who have 2 children. one of the children, a boy, comes into the room. find the probability <math>p</math> that the other is also a boy.
(a)1/3
(b)2/3
(c)1/2
(d)3/4
Since, it's given that the first one is a boy, the second event is independent of the first and the probability is 1/2. Had it been "one of the children is a boy" instead of "first one is a boy" then the probability of two children being boys would have been 1/3 (sample space BB, BG, GB).
A man visits a couple who have 2 children. one of the children, a boy, comes into the room. find the probability <math>p</math> that the other is also a boy.
(a)1/3
(b)2/3
(c)1/2
(d)3/4
Since, it's given that the first one is a boy, the second event is independent of the first and the probability is 1/2. Had it been "one of the children is a boy" instead of "first one is a boy" then the probability of two children being boys would have been 1/3 (sample space BB, BG, GB).