'Thirty' in the Bible

Then brought he me into the outward court, and, lo, there were chambers, and a pavement made for the court round about: thirty chambers were upon the pavement.

And the side chambers were three, one over another, and thirty in order; and they entered into the wall which was of the house for the side chambers round about, that they might have hold, but they had not hold in the wall of the house.

In the four corners of the court there were courts joined of forty cubits long and thirty broad: these four corners were of one measure.