Plash drives from city A to B at 40 km per hour and returns over the same road at 30 km per hour and spends 8 hours away from...

Plash drives from city A to B at 40 km per hour and returns over the same road at 30 km per hour and spends 8 hours away from home including a one hour stop for lunch. what is the distance (in km) between city A and city B?