A unit rate means a rate for one of something. We write this as a ratio with a denominator of one. For example, if you ran 70 yards in 10 seconds, you ran on average 7 yards in 1 second. Both of the ratios, 70 yards in 10 seconds and 7 yards in 1 second, are rates, but the 7 yards in 1 second is a unit rate…
a) 50km/2h
=> 25 kilometers per hour
b) 540kg/3d
=> 180 kilogram per day
c) 125m/5min
=> 25 meter per minute