You walk up to a mountain that has two paths. One leads to the other side of the mountain, and the other will get you lost forever. Two twins know the path that leads to the other side. You can ask them only one question. Except! One lies and one tells the truth, and you don't know which is which. So, What do you ask?
You ask each twin "What would your brother say?"
This works because.... Well let's say the correct path is on the left side. So say you asked the liar "What would your brother say?" Well, the liar would know his brother was honest and he would say the left side, but since the liar lies, he would say right. If you asked the honest twin the same question, he would say right, because he knows his brother will lie. Therefore, you would know that the correct path was the left.
There was once a college that offered a class on probability applied to the real world.
The class was relatively easy, but there was a catch.
There were no homework assignments or tests, but there was a final exam that would have only one question on it.
When everyone received the test it was a blank sheet of paper with a solitary question on it: "What is risk?"
Most students were able to pass, but only one student received 100% for the class!
Even stranger was that he only wrote down one word!
What did he write?
A very vicious dog is tied to a tree. If you came close enough, you'ed lose your head. If he sees you, he'll follow your every step. Your basket ball rolls past the dog. If you are alone, how do you get your ball back with out being mutilated?
Walk around the tree until there is no more rope left on the dogs leash. Then, grab your ball.