yeah its really an interesting one. I think I can solve.
At the end each box has 160 oranges so before we move 1/6 oranges from box C to box A so there must be (128,160,192) oranges in each box. So when we moved 1/5 of the oranges from box B to box C we must have had (128,200,152) oranges in the boxes. and when we moved 1/3 from A to B we must have had (192,136,152) oranges in each box.
Am I right?