Here is what you said;
Now if your answer is zero then there would be 50 amps on one side and 50 amps on the other side not a total of 100. All the current flow from one leg would be returning on the other leg if there was no current on the neutral.
If I used an ammeter and checked the amperage on the two legs of the feeder and found 50 amps on one leg and 40 amps on the other leg there would be 10 amps on the neutral and the entire 240 volt circuit would be drawing 50 amps not 90 amps.
There would be 40 amps of 240 volt current and 10 amps of 120 volt current even if everything on these feeders was 120 volt circuits.
If you are saying that on one side of the circuit there is 50 amps what you are saying is that there is 50 amps returning on the neutral. If you say that the other side is carrying another 50 amps then this current is returning on the neutral. If you are saying that 50 plus 50 equals 100 then this is saying that one side has 50 amps on the neutral and the other side has 50 amps on the neutral and this equals 100 amps on the neutral.
If you are saying that the two sides would balance the neutral and there would be no current on the neutral then just how is this current returning? It must be returning on one of the hot conductors.
No insults are intended just trying to get you to understand that the two donít add up.