I have found that one can indeed install multiple versions of Blender on the same system. I wasn’t sure about the original answer as I had just watched a tutorial introducing the new features in Blender 2.8 which switched between 2.80 and 2.79 several times. So I searched the web and found an earlier query on the same subject.
See the link below if you wish to have multiple versions of Blender on the same Windows system.
Installing multiple version of blender - Support / Technical Support - Blender Artists Community