Question

A race track is in the form of ring whose inner and outer circumstances are $352meters$ and $396meters$ respectively. Find the width of the track.

• A. $7meters$
• B. $14meters$
• C. $14\pi meters$
• D. $7\pi meters$

Answer 1

Answer: (A)

$7meters$

Let, $R,r$ be the outer and inner radius of the track then,

$2\pi R=396m$

$2\pi r=352m$

Now , $2\pi R-2\pi r=396-352$

$⟹2\pi (R-r)=44$

$⟹2\times \frac{22}{7}\times (R-r)=44$

$⟹R-r=44\times \frac{7}{44}$

$\therefore R-r=7m$

i.e., The width of the track $=7m$

Option A is correct.