Logic Riddles

Question: A very important man is about to take a trip to Iceland. He is awoken in the middle of the night by his security guard the night before he is supposed to leave. His guard tells him he needs to take a boat rather than a plane, because he just dreamt that the plane was going to crash. The guard leaves because it's the end of his shift.

The man listens to his guard and takes a boat. Soon after arriving in Iceland he hears that the plane he was supposed to go on crashed. When he arrives home he fires his guard.

Why?

Question: If you have a cake, how many pieces of cake can you form with 3 straight cuts?

Question: Tom and Joe want to sit behind each other in class and the teacher arranges them so they are both happy.

How did the teacher do so?

Question: If your overweight father-in-law, mother-in-law who looks like she's about to die, and your wife approach you in your car but you only have one other seat, who would you take?

Question: There are 3 switches downstairs, each corresponding to one of the light bulbs upstairs. How can you figure out which light switch goes to which light bulb by only making 1 trip upstairs?