Question

A car travels $1320m$ distance in which each wheel makes $420$ complete revolutions. Find the radius of its wheel $(\text{Take}\pi =\frac{22}{7})$.

• A. $30.30cm$
• B. $50cm$
• C. $32cm$
• D. $45cm$

Answer 1

The correct option is B $50cm$

Given: Distance covered $=1320m$, Revolutions made by each wheel $=420$

Let the radius of the wheel be $r$.

Circumference of a circle is given by the formula $2\pi r$.

$2\pi r\times 420=1320$

$2\times \frac{22}{7}\times r\times 420=1320$

$r=\frac{1320\times 7}{2\times 22\times 420}$

$r=\frac{1320}{2\times 22\times 60}$

$r=\frac{22}{2\times 22}$

$r=0.50m$

$1m=100cm$

Therefore, $0.50m=50cm$