A circular road runs around a circular garden. If the difference between the circumference of the outer… · ABC26GN4590
Subject: General Aptitude · Chapter: Area · Exam: M.A.T. 2007
A circular road runs around a circular garden. If the difference between the circumference of the outer circle and the inner circle is 44 m, the width of the road is
(a)3.5 m
(b)4 m
(c)7 m
(d)7.5 m
Answer
Answer (as printed): C
Explanation
Let the radii of the outer and inner circles be $R$ and $r$ respectively. Then, $2 \pi R-2 \pi r=44 \Rightarrow 2 \pi(R-r)=44$ $$\Rightarrow(R-r)=\frac{44 \times 7}{22 \times 2}=7 .$$
Explanation as extracted from the printed page; notation may be imperfect.