I don't think so. You don't include the time of the first car because it isn't the one catching up. Only one car is doing the "catching up" and that is the second car and it only takes 1 hour, the first car is just driving not catching up to anything so it can drive for 10 hours and it doesn't matter, it's how long it takes car 2 to catch up with car 1 and that is 1 hour.