Which of the following is best represents the average speed of a fast runner? 10 meters per second 10 miles per second 10 centimeters per hour 10 kilometers per second ( eeek! )

The first choice (10 m/s) best represents the speed of a fast runner.

Usain Bolt's world record in the 100 Meters is 9.58 seconds.
That's 10.44 meters per second ... about 23.4 miles per hour.

The other choices are out in Lala Land:

-- 10 miles per second . . . . . 3,600 miles per hour

-- 10 centimeters per hour . . . . . 0.000062 mile per hour
(more like MY running speed, but not like a fast runner)

-- 10 kilometers per second . . . . .  22,369 miles per hour