Answer :
A unit rate would be a ratio where 1 is the denominator . . .
(2000 rotations)/(40 sec)
2000/40
200/4
50 rotations/sec
(2000 rotations)/(40 sec)
2000/40
200/4
50 rotations/sec
[tex]speed=\frac{number\ of\ revolutions}{time}\\number\ of\ revolutions=2000\\time=40s\\\\
speed=\frac{2000}{40s}=50\frac{rotations}{second}\\\\Answer\ is\ 50\frac{rotations}{second}.[/tex]