Solution for #37

1 sees 2 and 3. If 1 saw two black hats or two white hats, then he would be able to guess the color of his hat. But in this case, he doesn't -- he sees a white hat and a black hat. Some time passes, and 2 realizes that 1 is not sure what color hat he's wearing. The only way 1 wouldn't be sure is if 2 and 3 are wearing differently colored hats. 2, who sees what color hat 3 is wearing (black), correctly names the opposite color as the color of his own hat.