I really think Moses made up this story to try to get the Hebrews now under his command to be good little boyz and girlies and stop killing each other, fokking each other's wives, lying, stealing, and being jealous.Adam and Eve had access to the Tree of Life in the garden. They disobeyed and were cast out. They carried out a sack of the fruit and passed them down to the patriarchs. The sack was empty shortly after Noah.
Of coarse he lived 950 years.