A man was eating at a restaurant. When his food came, his waitress told him that they had run out of their usual fancy dinner plates and had to serve him their only plain dish. The man did not object, but there was a bug on his food. His waitress took it away and said she would bring him a new plate with new food. When she came back, the man knew she had only tossed off the bug. How?
Solution
His waitress had told him she served him their only plain dish. When she brought his “new food”, it was on the same dish.
