Boy Girl (if first is boy, second can be girl or boy)
Boy Boywww.ddhw.com
Boy Boy(if second is boy, first can be girl or boy)
Girl Boy
You foget the possibility of "Boy Boy" should be counted twice.
The answer of second question is somewhat not correct. Because if the first is boy, then the seond is more likely to be a boy. You can use samples to get this. This is a biological reason. As such, strictly saying, the answer of the first question is also boy.
Yes, the answer to question one is definitely wrong. The author was arguing that the chances (or probability) of it being a girl is 2/3. However, that statement is wrong. It was based on the assumption that:
BG 1/3
GB 1/3
BB 1/3
However, if we are to work it out that way, it should be:
B1 G1 1/4
G1 B1 1/4www.ddhw.com
B1 B2 1/4
B2 B1 1/4
As stated by a previous poster, the BB combination should be counted twice. As such, it will end up that there is a 50/50 chance of it being a Girl or Boy.
So teh conclusion is: The guy should have his pay deducted by 10000USD per month!!!!
Yes, the answer to question one is definitely wrong. The author was arguing that the chances (or probability) of it being a girl is 2/3. However, that statement is wrong. It was based on the assumption that:
BG 1/3
GB 1/3
BB 1/3
However, if we are to work it out that way, it should be:
B1 G1 1/4
G1 B1 1/4
B1 B2 1/4
B2 B1 1/4www.ddhw.com
As stated by a previous poster, the BB combination should be counted twice. As such, it will end up that there is a 50/50 chance of it being a Girl or Boy. www.ddhw.com
So teh conclusion is: The guy should have his pay deducted by 10000USD per month!!!!
or not does not matter. The probability of the sex of the second is the same. The second analysis in your argument is the only right analysis. I don't understand how do you get the first analysis. Your first analysis is just wrong.
The following problems have the same answer:
1. I have two kids, the first is a boy, what is the probability of the second one is a boy?
2. I have two kids, what is the probability of the second one is a boy?