The inner circumference of a circular race track, 14m wide is 440m. Find the radius of the outer circle.

let inner radius be r meters. 

$2\mathrm{\pi r}=440\Rightarrow r=440\times \frac{7}{44}=70m\mathrm{radius} \mathrm{of} \mathrm{outer} \mathrm{circle} =70+14m$  

Therefore, Radius of outer circle = 70 + 14 = 84m