Good Riddles

Question: There are 100 prisoners lining up to go to jail. Each prisoner is wearing a hat that is either black or white. The prisoners don't know their own hat color, just the hat color of those in front of them in line (the first prisoner in line can't see anyone's hat and the last prisoner can see everyone's hat except their own). Starting from the back, one of the guards asks each prisoner what color their hat is. If they are correct they get to go free but if they are wrong they go to jail.If the prisoners get to discuss a plan, how can at least 99 of them be saved?

Question: A man is stuck on an island with his best friend and a fisherman. The fisherman and his best friend go off to catch food while he builds a hut. The fisherman returns alone with some salmon he had prepared. His best friend had fallen off a cliff.

After he is rescued from the man goes to a diner and he orders salmon. He eats his meal, he pulls out a gun and commits suicide. Why does he do this?

Question: Four hikers are forced into a cabin with no lights by a bad storm. On the door of the cabin is a sign that reads, "Come in as you please, but fall asleep and you will die." Being very superstitious, they all take this very seriously and devise a plan so they can all stay awake. They all stand in a corner and one person walks from one corner along the wall to the next and taps the person in that corner making sure they are awake. They do this for many hours until one hiker suddenly runs out of the cabin screaming along with all of the others.Why did they run out terrified?

Question: What is brown or silver, has a head and tail but no arms or legs?

Question: I have a few points but we're not competing.
And I'll help you win when you're eating.

What am I?