A child in a boat throws a 6.40kg package out horizontally with a speed of 10.0 m/s. Calculate the velocity of the boat immediately after, assuming it was initially at rest. The mass of the child is 26.0 kg, and that of the boat is 45.0 kg. Ignore water resistance. Characterize this interaction as elastic/inelastic/completely inelastic and determine the total work performed by the child.