[ronniejames]

Mike, read Sklansky's words: "To get the right answer, you would in fact have to subtract the number of redheaded boys from 17." Now, you can't subtract any number of redheads from 17 that will yield an answer of 19! If we agree that there are 17 boys and 4 redheads, then the number of children who are either boys or redheads can be 21 (if all the redheads are girls), 20, 19, 18, or 17 (if all the redheads are boys). So, if Sklansky wants us to subtract the number of redheads from 17, something is obviously wrong: he should be asking us to subtract from 21. I suggest that he intended to write, 13 BOYS and 4 redheads, and somehow it came out in print as 13 GIRLS.