1 while some of the questions are interesting (e.g. what is the number one threat to humanity?). It'll be tough to answer the humanity question in fewer than 500 words.
You come to a fork in the road where there are two guards standing. There are two roads you can take - one way provides safe passage while the other is populated with bandits. One of the guards always tells the truth, while the other always lies, but you don't know who does what.
You are only allowed to ask one question to figure out which is the safe road. What is the one question?
The biggest threat to humanity?
In a word, vampires.
Ask, "which road will the other guy tell me to take?".
