The following is a little preview a wonderful new book about problem-solving. (See below for more information.)
Solution: Let's figure out the answer by eliminating the ones we know are wrong. Choice (A) can't be right because then both children would be wrong. Choice (B) can't be right because Juan would be wrong, and we can eliminate choice (C) because it would mean that Lashana were wrong. But if we have eliminated (A), (B), and (C), then all we have left is (D). How could it be right? Choice (D) could be right if there were 3 horses on one side and 4 on the other, so that MUST be true!
Now use what you have learned to solve this harder problem: