'Thirty' in the Bible

Solomon’s food [for the royal household] for one day was thirty kors of finely milled flour, sixty kors of wheat flour,

The length of the house which King Solomon built for the Lord was sixty cubits (90 ft.), its width twenty (30 ft.), and its height thirty cubits (45 ft.).

He also built the House of the Forest of Lebanon; its length was a hundred cubits (150 ft.), its width fifty cubits (75 ft.), and its height thirty cubits (45 ft.), upon four rows of cedar pillars, with cedar beams upon the pillars.

He also made the Hall of Pillars; its length was fifty cubits (75 ft.) and its width thirty cubits (45 ft.). There was a porch in front, and pillars and a threshold in front of them.

Now he made the Sea (basin) of cast metal, ten cubits from brim to brim, circular in form, five cubits high and thirty cubits in circumference.