When did they invent a car?

There's no single answer to when a "car" was invented. The development of the automobile was a gradual process with many contributors. However, Karl Benz is generally credited with inventing the first practical automobile in 1886. His Benz Patent-Motorwagen is widely considered the ancestor of the modern car. Other inventors were working on similar vehicles around the same time, but Benz's design was the first to be truly successful and commercially viable.