I can't find rails version on the server that host a rails website

First of all, I am newbie to rails. i have a website that is written in rails this website is hosted on Ubuntu 14.04 server.when i write rails -v it gives me.

The program 'rails' can be found in the following packages: * ruby-railties-3.2 * ruby-railties-4.0 Try: apt-get install <selected package> However, this website is running on this server, so how can i check the rails version on it?