If it takes Charlie .45 hrs walking at 2.5 km/hr to get to the chocolate factory and it takes Willy Wonka 25 hrs walking at 3.5 km/hr then who lives closer and by how far?

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.