[_a_a_a_]

Why? So long as you know the probabilities and they are tolerable, why?

[kardos]

The challenge is to get the right answer. It's much less interesting if you relax the challenge to no longer require the right answer. Here's a really fast approximate answer: 50000000*(2^31-1)/2

[sYnfo]

Map vs. territory. The challenge, as defined by the system the competition runs on, is to get 3 correct responses in a row. That's it.

[nerdponx]

The fact that it's wrong sometimes is a lot less interesting than the probability distribution of wrongness, conditional on magnitude.

[Neywiny]

Solid point and good example