Good Riddles

Question: My name is Ruger. I live in a farm. There are four other dogs in the farm with me. Their names are Snowy, Flash, Speed, and Brownie. Who is the fifth dog?

Question: In the harbor of a small town, there is a large boat. Coming off of the boat is a ladder reaching down so that the bottom rung is just above the surface of the water. As the tide comes in, the water rises at 1 foot every 30 minutes, and continues like this for 3 hours. If the rungs are each 1 foot apart, how many rungs are under water when the tide stops rising?

Question: Without me, nothing exists. What am I?

Question: A criminal is brought into a prison for major crimes. The warden informs him that he will be shot in the middle of the prison by 20 of his men. The prisoner is fine with that but he asks for some conditions "All of your men must stand 20 feet away from me and I must be able to select where each of them stands. If I survive, I get to leave."

The warden thinks about it and knows that all of his men will still have an open shot at the criminal, so he agrees.

The next day immediately after the firing squad is positioned the criminal walks out untouched. How did he do it?

Question: You struggle to regain me.
When I'm lost, you struggle to obtain me.
I pass no matter your will,
but I'm your slave to kill.
What am I?