An olympic runner competing in a long-distance event finishes with a time of 2 hours , 15 minutes , and 23 seconds . the event has a distance of 25.5 miles . what is the average speed of the runner in kilometers per hour?

The average speed of the runner is 18.2 km/h.

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.