a student driving a car travels 10.0 km in 30,0 min.What was her average speed?

10 km/(0.5 h) = 20 km/h

There must be a lot of traffic or stop lights.

To find the average speed of the student driving the car, we need to divide the total distance traveled by the total time taken.

Given:
Distance traveled = 10.0 km
Time taken = 30.0 min

Step 1: Convert the time to hours
Since the distance is given in kilometers, let's convert minutes to hours. We know that there are 60 minutes in 1 hour.

30.0 min ÷ 60 = 0.5 hours

Step 2: Calculate average speed
Average speed = Distance ÷ Time

Average speed = 10.0 km ÷ 0.5 hours

Average speed = 20 km/hour

Therefore, the student's average speed was 20 km/hour.