When the switch is closed, the current in the wire would give rise to a magnetic field and the interaction of the two magnetic fields results in a magnetic force acting on the wire. According to the Newton's third law, a magnetic force would act on the magnet due to the wire, which is the reading of 161 g. (I did not state the direction of the force - I hope you can figure it out or else reply to ask for help).
Remember the question ask when the current is reversed and doubled......
I did not give the full solutions but I hope the hints are enough for you work out the answer.