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Recreational Mathematics: The Trouble with Boys
Posted: Sun May 30, 2010 8:10 pm
by Occulus
I have two children. One is a boy born on a Tuesday. What is the probability I have two boys?
The answer, as well as a full explanation, can be found at the end of
this New Scientist article.
Good luck!
Posted: Sun May 30, 2010 8:41 pm
by chrismb
I didn't know Martin Gardner had departed... I expect he is embedded in a state of pure logical being in one of his circular arguments somewhere...
The 'statistical' thing is a bit of a distraction trick. I do like it, but the flaw is simply that probability isn't just the number of possible ways of doing something because there is also a likelihood of that way of doing something. All possible permutations of an outcome do not share the same probability of occurrence. (The following comments didn't seem to notice/include this 'sleight-of-hand' trick either.)
The article uses the following logic, but less extremely so you don't notice: There is one Queen in the UK and 60 million people. If I dial a random telephone number into my phone there are two outcomes - I'll get the Queen's phone, or I'll get someone elses. So there's a 50% chance I'll get to speak with the Queen on her private number, if I dial in a random number.... If I dial 10 random numbers, the chance that I don't get through to the Queen is less than 1000 to 1! Hmmm....