'Thirty' in the Bible

Solomon’s provision for one day was thirty kors of fine flour and sixty kors of meal,

As for the house which King Solomon built for the Lord, its length was sixty cubits and its width twenty cubits and its height thirty cubits.

Now he made the sea of cast metal ten cubits from brim to brim, circular in form, and its height was five cubits, and thirty cubits in circumference.