1. The problem statement, all variables and given/known data This should be quite simple for most of you although I can't understand it. Circuit is attached below 2. Relevant equations 3. The attempt at a solution The answer is 20ohms, although I would have done R1+R3 + R4//R5 which would get 25ohms. The previous question was to find Rab and Rab = 25ohms. How do i view the circuit to get 20ohms? I'm aware it would just be R1+R3, but why can't you do it my way?