Question

The inner circumference of a circular race track is 264m and the width of the track is 7m. Calculate the cost of putting up a fence along the outer circle of the track at the rate of rupees 15 per metre.​

Answer 1

Answer:

Let r be the radius of the inner track.

Inner circumference of track =2πr=264m(Given)

⇒2×722×r=264

⇒r=264×2×227

⇒r=42m

Width of track (w)=7m(Given)

∴ Outer radius (R)=r+w

=42+7=49m

Therefore,

Outer circumeference of track =2πR

=2×722×49=308m

Cost of fencing =Rs.15 per meter

Therefore,

Cost of fencing the outer circumference of track =15×308=Rs.4620