i have this problem that ive been trying to figure out for a while, and cant seem to get it. Ricardo, of mass 87 kg, and Carmelita, who is lighter, are enjoying Lake Merced at dusk in a 28 kg canoe. When the canoe is at rest in the placid water, they exchange seats, which are 3.3 m apart and symmetrically located with respect to the canoe's center. Ricardo notices that the canoe moves 57.6 cm horizontally relative to a pier post during the exchange and calculates Carmelita's mass. What is it? ive been trying this from many different ways. Ive tried using the canoe after they move as the center of gravity, and then using x as the mass of the girl. I multiply the masses time the distance away from the center of gravity(the canoe) all divided by the mass, but its not coming out to the right answer. Can anyone help me with this?