You could think of this problem as you did, in a "simple way", because it depends what level is required from your solution. If it's quite easy, so be it. But your instructor needs a precise, real-world solution, you should be aware of the length of the two wires, which affects the resistance of the cables, and thus the thermal dissipation in'em would be less/more considerable. The heat produced by each cable could affect the other; consequently, its resistivity will change. Also, the higher the frequency of the signal carried out, the higher the possibility of the two cables to react as inductors, which is also dependent on the way they are placed (wired around each other, which is..., or just parallel, and what kind of shield or protection each wire has. Because, hey, they could be shielded, no?)... I hope I helped you in your quest :wink: ....