1. The problem statement, all variables and given/known data http://www.freeimagehosting.net/jqqoz 2. Relevant equations V(output) = V(input)(R2/R1) 3. The attempt at a solution The equation above is valid if the back part of the upper circuit (involving R3,R4 and the earth wire) does not exist. I tried to improvise with it by using the equation V(output) = V(input)(R2+1/(1/R3+1/R4))/R1 however the answer is wrong. Just need some guidance as to what I am doing wrong.