'Thirty' in the Bible

And the angel said to me, “What do you see?” And I answered, “I see a flying scroll; its length is twenty cubits (thirty feet) and its width is ten cubits (fifteen feet).”

I said to them, “If it seems good to you, give me my wages; but if not, do not.” So they weighed out thirty pieces of silver as my wages.

Then the Lord said to me, “Throw it to the potter [as if to the dogs]—that magnificent sum at which I am valued by them!” So I took the thirty pieces of silver and threw them to the potter in the house of the Lord.