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Post by abacus9900 on Sept 22, 2010 13:41:23 GMT 1
An unrelated woman and man each have two children. At least one of the woman's children is a boy, and the man's older child is a boy.
Are the chances equal that they both have two boys?
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Post by jonjel on Sept 22, 2010 14:23:37 GMT 1
That would depend on whether these progeny were the result of these unrelated people copulating together...  |
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Post by abacus9900 on Sept 22, 2010 14:33:29 GMT 1
That would depend on whether these progeny were the result of these unrelated people copulating together... Ah, you've begun to work it out.  |
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Post by jonjel on Sept 22, 2010 15:33:10 GMT 1
Well, it wasn't too hard.
As the unrelated woman said to the unrelated man....
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Post by abacus9900 on Sept 22, 2010 17:54:32 GMT 1
No, the answer is: 1/3 chance that the woman has two boys and 1/2 chance that the man has two boys.
Can you see why? Clue: we don't know which of the two children is a boy so we have to list all possible combinations, which is the way a computer would work it out, lacking common sense.
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