Final answer:
The student's average speed was 4 km/h.
Step-by-step explanation:
The average speed can be calculated by dividing the total distance traveled by the total time taken.
In this case, the student walked 1.5 km in 25 minutes, and then ran 0.5 km in 5 minutes.
Therefore, the total distance traveled is 2 km (1.5 km + 0.5 km) and the total time taken is 30 minutes (25 minutes + 5 minutes).
To calculate average speed, we divide the total distance by the total time:
Average speed = total distance / total time
Substituting the values, we get:
Average speed = 2 km / 30 min
Converting the time to hours (30 min = 0.5 h), we can simplify the expression:
Average speed = 2 km / 0.5 h
Solving for average speed, we get:
Average speed = 4 km/h