Cars

Question: There are two cars. The suburban is going 50 mph, and the mini van is going 30 mph. Although, the minivan passes the suburban and both cars are still going the same speed that they started at. How?

Question: Surrounded by life , yet life is its biggest enemy. But without life there is no need for it to exist. What is it?

Question: During what month do people sleep the least?

Question: When is 99 more than 100?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?

Question: The more you add, the less it weighs.