If a marathon runner speeds up from 8 m/s to km/h, how fast are they running?

To convert the speed of the marathon runner from meters per second to kilometers per hour, you can use the conversion factor that 1 m/s is equivalent to 3.6 km/h.

Starting with the runner's speed of 8 m/s, you multiply this value by 3.6:

8 m/s × 3.6 km/h = 28.8 km/h.

This calculation shows that if the runner is moving at 8 meters per second, their speed in kilometers per hour is indeed 28.8 km/h. Therefore, the correct answer aligns with this conversion, confirming that the runner's speed is accurately represented.