[ronniejames]

You need to read more carefully. You'll notice that you consider that the answer might be 19. Sklansky writes: "To get the right answer, you would in fact have to subtract the number of redheaded boys from 17. See why?" There are two possible typos in the column. If the published "13 girls" was intended to be '13 boys', then everything else is correct. If, as you suggest, we are to subtract the 13 girls from a total of 30 children, giving us 17 boys, then the two places where the number 17 appears should read, 21. I do not, even for a moment, entertain the possibility that Sklansky gave the wrong answer. It's too simple and he's far too competent.