The number of revolutions a wheel of radius 21 cm makes in travelling a distance of 198 m is:

Correct option is D

Given:

Radius of the wheel = 21 cm

Distance travelled = 198 m = 19800 cm

Formula Used:

Circumference = $$2\pi r$$​

​$$\text{Number of revolutions} = \dfrac{\text{Total distance}}{2\pi r}$$​​

Solution:

​$$\text{Circumference} = 2 \times \dfrac{22}{7} \times 21 = 132 \text{ cm} \\ \text{Number of revolutions} = \dfrac{19800}{132} = 150$$​