3 rev s-1
40 rev s-1
360 rev s-1
2400 rev s-1
Correct answer is C
\(\frac{\text {speed of driver}}{\text {speeder driven}}\) = \(\frac{\text {no. of teeth of driver}}{\text {no. of teeth of driven}}\)
\(\frac{120}{V}\) = \(\frac{20}{60}\)
v = 360 rev s-1