Answer:
The average speed of the runner is 18.2 km/h.
Step-by-step explanation:
Hi there!
The average speed is calculated as the traveled distance over time:
speed = traveled distance / elapsed time to cover that distance
We have to find the speed in km/h, so let´s start converting the time into hours:
23 s · (1 min/60 s) = 0.38 min
15.38 min · (1 h / 60 min) = 0.26 h
Total time: 0.26 h + 2 h = 2.26 h
The distance traveled in km is:
25.5 mi · (1.61 km/ 1 mi) = 41.1 km
Then, the average speed will be:
speed = 41.1 km / 2.26 h = 18.2 km/h
The average speed of the runner is 18.2 km/h.