SOLUTION: Christina is planning on having 7 children. a. Determine the probability that all of her children will be girls. b. If her first 6 children are boys and she is expecting anot

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Question 1118179: Christina is planning on having 7 children.
a. Determine the probability that all of her children will be girls.
b. If her first 6 children are boys and she is expecting another child, what is the probability that her 7th child will be a girl?
Found 2 solutions by Fombitz, ikleyn:
Answer by Fombitz(32388) About Me  (Show Source):
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With 6 children, there are 2%5E6 possible combinations.
One of them is all girls so,
P%28GGGGGG%29=1%2F2%5E6=1%2F64
.
.
.
The assumption is that each event is independent so,
P%28G%29=P%28B%29=0.5

Answer by ikleyn(52824) About Me  (Show Source):
You can put this solution on YOUR website!
.
Christina is planning on having 7 children. 

a.  Determine the probability that all of her children will be girls.


       - This probability is  %281%2F2%29%5E7 = 1%2F2%5E7 = 1%2F128 = 0.0078 = 0.78%.



b.  If her first 6 children are boys and she is expecting another child, what is the probability that her 7th child will be a girl?


        - I don't know what Biology says in this case . . . 

          But the standard probabilistic model says that this probability is  1%2F2 = 0.5 = 50%.