To calculate the average speed of the child, we first need to determine the total distance traveled and the total time taken.
Total distance traveled:
The child travels 900 meters from the starting point to the end of the road and then returns to the starting point, which means the total distance covered is 900 meters + 900 meters = 1800 meters.
Total time taken:
The child takes one-fourth of an hour to complete the round trip. Since one hour is equal to 60 minutes, one-fourth of an hour is equal to 15 minutes.
Convert the total time to hours:
Total time in hours = 15 minutes / 60 minutes per hour
Total time in hours = 0.25 hours
Calculate the average speed:
Average speed = Total distance / Total time
Average speed = 1800 meters / 0.25 hours
Average speed = 7200 meters per hour
Therefore, the average speed of the child on the round trip is 7200 meters per hour.