The distance for example could be in miles, feet, or meters. Just be sure that you do the proper conversions . Or, use a simple online unit converter HERE or a more detailed professional converter HERE . Also, be sure the units agree with one another. See our mathematics page for more information.
Physicists use the SI system of measurement which uses meters as the basic length unit.
In most cases it is much simpler to do calculations with SI units. If your distance is in meters and the time is in seconds then your speed answer will be meters per second. Makes perfect sense. Just do some thinking about the units your using. Yes, physics requires you to think.