A circular road runs round a circular ground. If the difference between the circumferences of the outer circle and the inner circle is 66 metres, the width of the road is
OPtion
1) 21 m
2) 10.5 m
3) 7 m
4) 5.25 m
5) 6 m
6) 6.5 m
7) 8 m
8) 8.2 m
9) 9 m
10)None of these
Solution
2 Pi R - 2 Pi r = 66
2 Pi (R-r) = 66
Therefore
R - r = (66/2 * 7/22) = 10.5 m