Explanation:
how should we express the speed ? in meters per second ? kilometers per hour ?
or anything else ?
he moves 250 meters in 500 seconds.
that is 250/500 m/s = 0.5 m/s (meters per second)
for kilometers per hour we need to convert this to an expression that bases on an hour instead of one second.
we know there are 3600 seconds (60 seconds × 60 minutes) in an hour.
and to keep the ratio unchanged, we need to do the same thing to the top and the bottom of it.
so, we multiply 0.5 m/s by 3600/3600.
0.5/1 × 3600/3600 = 1800/3600 m/s = 1800/1 m/h =
= 1.8 km/h
in other words - he is really slow. a normal person walks much faster.