The Matching Car
To pass the time while driving, you start looking for cars with
the same three-digit number on their license plates as you have
on your own. Assuming three-digit numbers
are uniformly distributed among the cars you'll be passing, what is the
average number of cars you'll pass before you'll see a matching car?
Now tired of that game, you exercise your memory - what is the average
number of cars you'll pass before you'll see a duplicated three-digit number?
Source: Reader Rich Polster.
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