question_answer

A circular road runs around 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: (Take\[\pi =\frac{22}{7}\])

A)  10.5 metres  

B)  7 metres

C)  5.25 metres 

D)  21 metres

Correct Answer: A

Solution :

Breadth of road\[={{r}_{2}}-{{r}_{1}}\] \[\therefore \,\,2\pi {{r}_{2}}-2\pi {{r}_{1}}=66\] \[\Rightarrow \,\,2\pi ({{r}_{2}}-{{r}_{1}})=66\] \[\Rightarrow \,\,{{r}_{2}}-{{r}_{1}}=\frac{66}{2\pi }=\frac{66\times 7}{2\times 22}=10.5\,meter\]