Finding Apache installation path and configuration file
There are several ways to determine, where Apache has been installed on your Linux/Unix system and what are other imporant paths for it (WWW root, configuration etc.). You can use this nice blog entry, which in general means executing
ps -ef | grep apache to determine path and then running
/usr/sbin/apache2 -V with proper path (replace
/usr/sbin/ part) to determine Apache configuration details.
You can also use DistrosDefaultLayout page in Httpd Wiki to find default path layout for your particular operating system.
If everything else fails, try to help yourself with Installation and setup of the Apache Web Server (Linux) document.