Algebra question!!! I need your help!!!!

in this situation, the answer is 120,80,40,
This is how I did it.
I plugged in 120*2 and got 240.
Then, I used the 80 and 40 (I added them separately)
240+80=320
240+40=280
120+80+40=120.
So, this matches the problem.
The answer is D