The ratio of the outer and the inner circumference of a circular path is 17 : 15, If the path is 40 metres wide, then what is the radius of the inner circle?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 300 metres.
Given that
The ratio of the outer and the inner circumference of a circular path is 17 : 15,
The width of the path = 40 m
Let the radius of outer circle and inner circle be R and r respectively
According to the question
The outer circumference/The inner circumference = 2πR/ 2πr = R/r = 17/15
The width of path = R - r = 17 - 15 = 2 units
⇒ 2 units = 40 m
⇒ 1 unit = 20 m
⇒ 15 units = 15 × 20 = 300 m
Hence, the inner radius r is 300 meters