SOLUTION: A family has three children. Every child was born to be a boy or girl with 50% chance. The probability if this family having three boys is:

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Question 992096: A family has three children. Every child was born to be a boy or girl with 50% chance. The probability if this family having three boys is:
Found 2 solutions by jim_thompson5910, solver91311:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
P(boy) = 0.5

P(3 boys) = P(boy and boy and boy)
P(3 boys) = P(boy)*P(boy)*P(boy)
P(3 boys) = 0.5*0.5*0.5
P(3 boys) = 0.125

The probability of having 3 boys is 12.5%

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!

I just answered this same question. Is there something wrong with the answer I posted?

The sample space is:
    B  B  B   **
    B  B  G   *
    B  G  B   *
    B  G  G
    G  B  B   *
    G  B  G
    G  G  B
    G  G  G

There are eight possibilities. Three of the possibilities have two boys (*), and one has three boys (**).

So the probability of EXACTLY two boys is 3/8. The probability of AT LEAST two boys is 1/2. What the question means by "two boys" is a matter of interpretation. You choose which is the correct way to look at it. The sentence as written is ambiguous and could mean either exactly or at least.

John

My calculator said it, I believe it, that settles it