'Thirty' in the Bible

Then he brought me into the outer court, and behold, there were chambers and a pavement made for the court all around; thirty chambers faced the pavement.

The side chambers were in three stories, one above another, and thirty in each story; and the side chambers extended to the wall which stood on their inward side all around, that they might be fastened, and not be fastened into the wall of the temple itself.

In the four corners of the court there were enclosed courts, forty cubits long and thirty wide; these four in the corners were the same size.