1. The problem statement, all variables and given/known data Prove that for a simple, connected, planar graph, 3f ≤ 2e where f = faces and e = edges 3. The attempt at a solution My professor went over this in class, and mentioned something about "double counting," which I do not really understand. I tried saying that it takes 2 counts to define an edge and 3 to define a face, but from here I am not sure what to do as I am unfamiliar with double-counting proofs. Thanks for the help.