Question

Bill is riding in a railroad car. He throws a ball towards the back wall of the car. The train is moving at constant 20 m/s to the right. The ball is flying away from Bill at 8 m/s. According to Bill, his 0.145-kg baseball has 4.64 joules of kinetic energy. His brother is standing on the ground disagreeing. According to him, the baseball has 10.44 joules of kinetic energy. Who is right?
Answer this in words, not equations, briefly explaining how you obtained your answer.