Question

The cost of fencing a circular field at $Rs.9.50$ per metre is $Rs.2926$. Find the cost of ploughing the field at $Rs.1.50$ per sq. metre.

• A. $Rs.11319$
• B. $Rs.12119$
• C. $Rs.10319$
• D. $Rs.13109$

Answer 1

The correct option is A $Rs.11319$

Let the radius of the circle be $r$.

Circumference of the circle is $2\pi r$

Thus,
$2\pi r\times 9.50=2926$

$\Rightarrow r=\frac{2926\times 7}{2\times 9.50\times 22}$

$\Rightarrow r=49$

$\Rightarrow r=49$ m

Thus, the cost of ploughing the field at Rs. 1.50 = Rs. $\pi (49{)}^2\times 1.5$

$=$Rs. $\frac{22}{7}(49{)}^2\times 1.5$

$=$Rs. $11319$