How long did the average dinosaur live

It all depends on whether your talking about herbivores or carnivores. If herbivores reach their full potential and size, they can get close to or above 100 years old. It's a different story for carnivores though. A big theropod could get to his 30's and maybe 40 for very few, raptors about in their 20's, flying reptiles (which were called pterosaurs and are not considered to be dinosaurs) could reach about 10 or 15, and smaller things like compsagnathus would have very wide ranges since we can't predict if it was a juvenile or not.