Riddle: Suppose you want to cook an egg for exactly 3 minutes. You have only a 5 minute hourglass timer and a 2 minute hourglass timer. Using these 2 timers, how can you boil the egg for exactly 3 minutes?
Answer: Tip both timers over at the same time. When the 2 minute timer runs out, drop the eggs in and cook them until the 5 minute timer runs out!