A B

12800[---------------------------------------------- --------]12800 up 1″

lbs. 161″ lbs.

Both A and B weight is 12800 lbs.

Arm between A and B is 161″

If B is elevated 1″, what will be resulting weight of A and B?

Just some food for thought...

To answer this question wouldn't it refer to how much the weight changes over the arm after B is elevated one inch?

Yes, your version of the question is correct. Sorry for any confuseion.