'Fifty' in the Bible

Suppose there are fifty righteous [people] within the city; will You really sweep it away and not spare it for the sake of the fifty righteous who are in it?

So the Lord said, “If I find within the city of Sodom fifty righteous [people], then I will spare the entire place for their sake.”

If five of the fifty righteous are lacking, will You destroy the entire city for lack of five?” And He said, “If I find [at least] forty-five [righteous people] there, I will not destroy it.”