Question

The outermost circumference of a circular track is 194.68 m and the track is everywhere 6m wide.Find the cost of levelling the track at the rate of 25 paisa per m.

Answer 1

Let the radius of outer circle be R

Given: Circumference of outer circle = 194.68 m

⇒ 2πR = 194.68 m
⇒ 2 × 3.14 R = 194.68 m
=>R=31m
⇒ Radius of inner circle (r) = Radius of outer circle – width
= 31 m – 6 m = 25 m
Thus area of track = area of outer circle – Area of inner circle
= πR²– πr² = π (R²- r²)=1056m²
Now cost of leveling 1 m2 = 25 paise = Rs 0.25

Hence cost of leveling track = Rs 0.25 × 1056 = Rs 264