Answer:
She is measuring her speed
Explanation:
Speed is defined as the ratio between the distance covered divided by the time taken to cover that distance:
[tex]v=\frac{d}{t}[/tex]
where
d is the distance covered
t is the time taken
Since Mary is measuring how far she can run in a given period of time, she is measuring the distance she can travel (d) in a given time (t), so she is measuring her speed.
