Thanks for your feedback!
I am new to RHEL (CentOS 7). Have been googling over the Internet to resolve the problem
but so far still struggling. I have installed PostgreSQL already and now trying to install
PostGIS. I see that EPEL already contains GEOS package and I don't need EL GIS repo.
Based on your comment, do you suggest to remove repositories which are not required?
Why I messed up with so many unwanted repositories because when I tried to install PostGIS
using this link:
http://www.postgresonline.com/journal/archives/362-An-almost-idiots-guide...
I ran into problems, then somehow I used other links of PostgreSQL 9.4 which was not
realistic somehow.