>Ok, here is a good one for the rule of 3.
>
>I need to know what this would give in km/h if we can do 5 meters in 5 seconds. So, basically, what is the equivalent of that speed in kilometers/hours.


1m/1c = 3600m/h = 3,6km/h

Good you didn't ask miler per hour, though, as I don't know in memory the conversion rate between miles and km.