Question

A race track is in the form of a ring whose inner circumference is $440m$ & outer circumference is $506m$ The width of the track is:

• A. $7m$
• B. $21m$
• C. $10.5m$
• D. $14m$

Answer 1

The correct option is C $10.5m$

Let the radius of the outer circle be R and inner circle be r.
Outer circumference $=506m$

$⟹2\times \frac{22}{7}\times R=506m$

$R=80.5m$

Inner circumference $=440m$

$⟹2\times \frac{22}{7}\times r=440m$

$r=70m$
Hence, width of the track $=(80.5-70)m=10.5m$