Tough Q

I love riddles that poke at the deficiencies in my brain, that really seem very counterintuitive.

One example is the famous Monty Hall Problem... once you know the answer it's easy to see why the correct answer is right, but the tougher problem is why you were wrong in the first place. That is, it's hard to see why the wrong answer seems right.

More worryingly, it's hard to tell how often an analogue to this puzzle pops up in daily life and how often I've been getting it wrong!

I think of these as optical illusions for my brain, but for some reason I'm a lot less worried about optical illusions for some reason. Of course when it really matters I just bust out a ruler, but it can be hard to even tell if it really matters if a certain answer just already looks obvious!

Anyway, here's the latest:

http://terrytao.wordpress.com/2008/12/09/an-airport-inspired-puzzle/

I've managed to convince myself that the correct answer is in fact correct, but it still blows my mind. I haven't yet fully wrapped my mind around it to the extent that the correct answer just seems natural and intuitive. What I think will seal the deal for me is figuring out the economic intuition behind this. Maybe I should just do the math for myself to see the details. Crazy stuff.