Question:
If $\pi$ is taken as $\frac{22}{7}$, the distance (in metres) covered by a wheel of diameter $35 \mathrm{~cm}$, in one revolution, is
(a) 2.2
(b) 1.1
(c) 9.625
(d) 96.25
Solution:
The disstance covered by the wheel in one revolution is equal to the circumference of the wheel.
Circumference $=\pi r^{2}$
$=\frac{22}{7}\left(\frac{35}{2}\right)^{2}$
$=\frac{22}{7}\left(\frac{35}{2}\right)^{2}$
$=962.5 \mathrm{~cm}$
The distance covered by the wheel in one revolution (in m) is given by
$\frac{962.5}{100}=9.625 \mathrm{~m}$
Hence, the correct answer is option (c).