A race track is in the form of a ring whose inner circumference is 352 m and the outer circumference is 396 m. Find the width of the track.

Explanation

Let R and r be the outer and inner radii of the circle
The width of the track `= (R - r) cm`
The width of the track = `(R - r) cm`
Now, `2 pi r = 352 " " rArr 2 xx (22)/(7) xx r = 352`
`rArr r = (352 xx 7)/(2 xx 22) = 7 xx 8 = 56 cm`
Again, `2 pi R = 396 " " rArr 2 xx (22)/(7) xx R = 396`
`rArr R = (396 xx 7)/(2 xx 22) = 7 xx 9 = 63 m`
`:. R = 63m, r = 56 m`
Width of the track `= (R - r) m = (63 - 56) m = 7 m`