Question

The radius of the wheel of a vehicle is 42 cm. How many revolutions will it complete in a 19.8-km-long journey?

Answer 1

Distance covered in one revolution= $2\pi R=2\times \frac{22}{7}\times 42=264$ cm

total distance= 19.8km= 1980000 cm

$\text{No. of revolutions}=\frac{\text{total distance}}{\text{distance covered in 1 revolution}}$

$\frac{1980000}{264}=7500$ revolutions