Love this comment.
The contestants' achievements were the results of endless hours of practice and not necessarily innate math (sic) abilities.
Have you read "thinking, fast and slow", Tighty. I have just started reading it, but I think it is going to be very good. Very much like "Fooled by Randomness". Anyway this looks a classic example. Your instinct tells you it is 50%, but you really need to step back and think the problem through. Unless it was in your practice questions anyway!