A 54-kg person at the southernmost end of a 150-kg rowboat at rest in the water begins to walk to the northern?

A 54-kg person at the southernmost end of a 150-kg rowboat at rest in the water begins to walk to the northern end. If, at a given instant, her speed with respect to the water is 13 m/s, what is the velocity of the boat with respect to the water at that moment? [Hint: The initial momentum of the system (boat and person) is zero and momentum is conserved.]