Physical quantities are measured as 'nu' where n is the magnitude and u is the unit. For example: A boy measured the length of a room as 3 m. Here 3 is the magnitude and m (metre) is the unit. 3 m can also be written as 300 cm.
No. The only European units I know of who were able to sustain that. kind of speed on foot were Foreign Legion-where the standard was 50. km per day. Other infantry units usually come in under 20 miles a day. (and closer to 12-15 miles per day).
Horses, mules, and donkeys (equines) move at a walking pace of about 4-5 miles per hour. A fast trot can be as much as 9 mlp, a gallop 20 or more. However, a gallop cannot be sustained all day, the animal would have to alternate with short bursts of speed and then periods of just walking or trotting.