I was asked this once during an interview. After I gave several lengthy possible explanations, the interviewer was basically speechless.
The previous question was much more interesting. I was asked to estimate the number of piano tuners there were in my city. I got it right, and it turns out it was one of the the class Fermi questions
Still, I'm not really a fan of these types of questions. Chances are any curious person who spends a lot of time on the net would have come across them some time or another.
The previous question was much more interesting. I was asked to estimate the number of piano tuners there were in my city. I got it right, and it turns out it was one of the the class Fermi questions
http://mathforum.org/workshops/sum96/interdisc/classicfermi....
Still, I'm not really a fan of these types of questions. Chances are any curious person who spends a lot of time on the net would have come across them some time or another.