Question: Why are manholes round instead of square?
Answer: If they are round the manhole covers cannot slip into the hole if the hole is slightly smaller than the cover, but if they are square the hole would have to be about 50 percent of the area of the cover to stop the cover from falling into the hole (diagonally).
Question: A man is found dead on a Sunday morning. His wife calls the police immediately. The police question the wife and staff. The wife said she was asleep, the cook said he was cooking breakfast, the gardener said she was picking vegetables, the butler said he was cleaning the closet, and the maid said she was getting the post. The police immediately arrested the murderer.Who was the murderer?
Answer: The maid because there's no post on Sundays.