We know that the distance, speed, and time it takes are all connected. Here are the three forms of the equation that describes the connection:
-- Distance = (speed) x (time)
-- Speed = (distance) / (time)
-- Time = (distance) / (speed)
Since the question is asking "How long ?", the answer will be a time. The easiest equation to use is the third one:
Time = (distance) / (speed)
Time = (650 km) / (80 km/hr)
Time = (650/80) ( km / km/hr)
Time = 8.125 hours
( Time = 8 hrs 7 minutes 30 seconds )