Equivalent resistance of a two pole

[faen]

1. The problem statement, all variables and given/known data

http://img.photobucket.com/albums/v488/nikko9000/skann0009.jpg

2. The attempt at a solution

I would say Re = 6 ohm, but that cant be right.. So i really dont know how it could be something else. Any help in solving this problem would be apreciated :)

[faen]

ok i think i got it now. its U/4SU = 1/4S