First you do 200/1.8 because you have to find how fast the swimmer swam.
200/1.8 = 111.1
Then you do 200/21.3 to find how many meters the runner ran per second.
200/21.3 = 9.4
The swimmer swam 1.8 meters per second and the runner ran 9.4 meters per second.
It took the swimmer 111.1 seconds to swim 200 meters, and it took the runner 21.3 seconds.
Hope this helps!
