Final answer:
The car is traveling at a rate of 100 kilometers per hour.
Step-by-step explanation:
To determine the rate of speed at which the car is traveling, we need to divide the total distance traveled by the time taken. In this case, the car travels 600 km in 6 hours. Therefore, the rate of speed is calculated as:
Speed = Distance / Time
Speed = 600 km / 6 hours
Speed = 100 km/h
So, the car is traveling at a rate of 100 kilometers per hour.