A canoe of mass 38 kg lies at rest in still water. A man and a woman are at opposite ends of the canoe 4.0 m apart and symmetrically located with respect to the canoe’s centre (which is also its centre of mass). The mass of the man is 65 kg and the woman’s mass is smaller.

The two people then change places and the man observes that the canoe shifts a distance 0.20 m relative to the water. What is the woman’s mass?