How to find out where ruby version that rails points to is present

Question

I have only ruby-2.3.7 in my machine and the output of the rvm list rubies is

=* ruby-2.3.7 [ x86_64 ]

# => - current
# =* - current && default
#  * - default

but when i try to do rails s I get an error saying Your Ruby version is 2.6.4, but your Gemfile specified 2.3.7

I'm not sure how to find out where this particular version of ruby exists in the machine and how to uninstall it or make this error go away.

I cannot change the version of ruby being used in the gemfile though.

Edit.

The output of which ruby is /Users/myname/.rvm/rubies/ruby-2.3.7/bin/ruby

the output of bundle env is

Bundler             1.17.3
  Platforms         ruby, x86_64-darwin-18
Ruby                2.3.7p456 (2018-03-28 revision 63024) [x86_64-darwin18]
  Full Path         /Users/bennetsunder/.rvm/rubies/ruby-2.3.7/bin/ruby
  Config Dir        /Users/bennetsunder/.rvm/rubies/ruby-2.3.7/etc
RubyGems            3.0.6
  Gem Home          /Users/bennetsunder/.rvm/gems/ruby-2.3.7
  Gem Path          /Users/bennetsunder/.rvm/gems/ruby-2.3.7:/Users/bennetsunder/.rvm/gems/ruby-2.3.7@global
  User Path         /Users/bennetsunder/.gem/ruby/2.3.0
  Bin Dir           /Users/bennetsunder/.rvm/gems/ruby-2.3.7/bin
Tools               
  Git               2.20.1 (Apple Git-117)
  RVM               1.29.8 (latest)
  rbenv             not installed
  chruby            not installed
  rubygems-bundler  (1.4.5)

Answer 1

I realised that I had installed ruby-2.6.4 view brew and it was on the path. To fix this you either do brew uninstall ruby and work with the one installed via rvm or remove the path entry which fetches from brew installation directory.