That is what I was thinking too, but the answer key to the book says 5.0m/s, but it doesn't explain why. Yeah, the mass of the passenger is 72 kg. The mass of the boat is 1000 kg.
Homework Statement
A boat is moving at .5 m/s relative to the ground with a passenger riding inside of the boat. If the passenger jumps off of the front of the boat at a velocity of 4.0 m/s (relative to the boat), what is the total velocity of the passenger relative the the ground/water...