we know that
The unit rate is the ratio of two measurements with the second term equal to one
In this problem to find the unit rate divided the total distance by the total time
so
[tex]\frac{692.08}{21.1} \frac{ft}{s}=32.8\frac{ft}{s}[/tex]
that means [tex]32.8[/tex] feet per second
therefore
the answer is
The unit rate is equal to [tex]32.8\frac{ft}{s}[/tex]