Riddle: A bus driver was heading down a street in Colorado. He went right past a stop sign without stopping, he turned left where there was a "no left turn" sign, and he went the wrong way on a one-way street. Then he went on the left side of the road past a cop car. Still - he didn't break any traffic laws. Why not?
Riddle: In a certain city, 5% of all the people in town have unlisted phone numbers. If you select 100 names at random from that city's phone directory, how many people selected will have unlisted phone numbers?
Answer: None. If their names are in the phone directory, they do not have unlisted phone numbers!