1. The problem statement, all variables and given/known data I'm studying for a test and since this is technically a textbook problem I figured I'd post here to prevent being flagged. I have the circuit redrawn. 2. Relevant equations Series: Req = R1+R2... Parallel: 1/Req= 1/R1 + 1/R2... 3. The attempt at a solution I want to understand why when solving this circuit for Req it is (3 || 30) || 7.5 = 2ohms. According to the solution I'm looking at the 75 ohm resistor is considered a short and no current flows across this? I don't understand why this is the case. Also I was originally trying to be lazy and solve and just add things up without redrawing the circuit and ended up with 2ohms by doing: ((5||20)+2)||3 = 2ohms Was this just coincidence?