Which Berkshire Hathaway business had the highest EBIT margin in 2013?

This might sound like trivia, but it's not -- facts like these can provide insight into some of these companies, and tell you where they might move in the future. In the following video, Motley Fool banking analysts David Hanson and Tyler Riggs discuss this week's "Stock Quiz" and why Berkshire Hathaway is looking to its railroad executive for more answers.