The ratio of the outer and the inner circumference of a circula path is 17 : 15. In the path is 40 metres wide, then what is the radius of the inner circle?
Answer & explanation
Correct answer: option 4
The width of the path = Outer radius(R) - Inner radius(r)
Ratio of outer(R) and inner(r) circumference = 2$\pi$R : 2$\pi$r = 17 : 15
⇒ R : r = 17 : 15
⇒ difference in the ratios = R - r = 2x
we know. that R - r = 40(width of the path)
⇒ 2x = 40
⇒ x = 20
Radius of inner circle(r) = 15 x 20 = 300m