Logic 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: 500 is at my end and my start, yet 5 is at my heart.
The first letter and the first number make me complete.
My name is that of a king.

What am I?

Question: A man is in court for killing his wife. In the closing statements the man's lawyer surprises everyone when he announces "His wife was just missing. Everyone look at those doors. His wife is going to walk in those doors in about 30 seconds."The entire court is silent and the jury stares at the door as the lawyer and the defendant stare at them. After a couple of minutes the lawyer says "See! If you were so sure he killed his wife, you wouldn't be watching that door!"The jury goes into deliberation and comes back almost immediately with a guilty verdict.Why did the jury convict him?

Question: A cheap man and his wife decide to go on a trip for their 10th anniversary. They go to Brazil and while touring the rain forest his wife falls off of a bridge to her death.

Shortly after her death one of the flight attendants on their flight sees a report on her death on television. She immediately calls the police and tells them the man murdered his wife.

How did she know?

Question: Two coins make 30 cents one of them isn't a nickel what are they?