This question is a self-obvious riddle that challenges your creative thinking and adaptability. It is designed to see how well you can shift gears from the traditional interview mode and how aptly you handle a challenge. The heart of these tests is frequently to test how you respond and not necessarily how quickly you can deliver an answer. For example, there's a story where a hiring manager asked a candidate, "Batman and Crabman got into a fight; who won?" The candidate asked, "Did they fight below or above water?" That answer got them the job. So, as with any question like this, it is all about communication and your analytical skills.