Question

A car has to travel 0.121 km to reach from A to B. If the radius of the tyre is 7 cm, how many times will the tire rotate while the car travels from A to B?
(Use π = $\frac{22}{7}$)

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Answer 1

Circumference of tyre = 2 πr = Distance travelled in each rotation = $2\times \frac{22}{7}\times 7$ = 44 cm.

Total distance covered = Number of rotations $\times$ Circumference of tyre

Number of rotations = $\frac{0.121km}{44cm}=\frac{0.121\times 1000m}{44\times 0.01m}=275$