I'm not sure if I got 2 or 3 wrong. I didn't know the NFS one, though IRL it wouldn't have taken long to figure out, nor did I know the umask one, mostly because I haven't trained myself to think of permissions as a number, but also because I don't like umask (and it was misleading anyway). I also got the /etc/passwd one "wrong" because is most Linux installs, the actual password is in another file.
Wade.