Two blocks are in contact on a horizontal, frictionless table. Block 1 has a mass of 4.39 kg and block 2 has a mass of 2.59 kg. A horizontal force of magnitude 8.25 N is applied to the one of the blocks. Find the magnitude of the force between the blocks (a) if the given force is applied to the larger block and (b) if the given force is applied to the smaller block. Find the difference between your answers to (a) and (b) (in Newtons).
We're given the answer already, but I have no idea about the steps on how to solve it.