A. Rate
 The quotient of two quantities measured in different units.
 "a" per "b" = a/b
 It’s the speed at which something is happening such as miles per hour, meters per second, or words per minute.


B. Ratio
 The quotient of two quantities measured in the same unit.
 "a" per "b" = a/b
 It’s used to show a comparison such as the ratio of boys to girls in a classroom.


