If a car travels at a constant average speed of 30 km/h for one hour, the distance it will cover can be calculated by multiplying the speed by the time. In this case, the car's speed is 30 km/h, and it travels for 1 hour.
Distance = Speed × Time
Distance = 30 km/h × 1 hour
Distance = 30 km
Therefore, the car will travel a distance of 30 kilometers.