Question

A roller of diameter $70cm$ and length $2m$ is rolling on the ground. What is the area covered by the roller in $50$ revolutions ?

• A. $220m^2$
• B. $230m^2$
• C. $210m^2$
• D. $330m^2$

Answer 1

The correct option is A $220m^2$

Since the diameter of the roller is $70cm$, its radius is $35cm$.
In one revolution, the wheel covers the distance of one circumference.
Circumference of the roller of radius $35cm$ an length $700cm=2\times \frac{22}{7}\times 35\times 200=44000{cm}^2$
Distance travelled in $50$ revolutions $=50\times 44000{cm}^2=220000{cm}^2=220m^2$