Question

The outer circumference of a circular race-track is 528 m. The track is everywhere 14 m wide. Calculate the cost of levelling the track at the rate of 50 paise per square metre (Use π = 22/7)

Answer 1

It is given that the outer circumference C of circular track is 528 m.

We know that the circumference of circle of radius r is

Substituting the value of C,

Thus, the radius of outer circle is.

Since circular race track is 14 m wide everywhere. Then

We know that the area of circle of radius r is

So,

Now,

It is given that,