SSC CGL Tier II 12 Jan 2017 Paper 1

(3) Area of circular field $=\frac{\mathrm{Total}\mathrm{Expenditure}}{\mathrm{Rate}\mathrm{per}\mathrm{square}\mathrm{metre}}$
$=\left(\frac{7700}{\frac{1}{2}}\right)$ sq. metre
= (7700 × 2) sq. metre
= 15400 sq. metre
If radius of field = r metre then,
$\mathrm{\pi }{\mathit{r}}^2=15400$
$\Rightarrow \frac{22}{7}{\mathit{r}}^2=15400$
$\Rightarrow {\mathit{r}}^2=\frac{15400\times 7}{22}=7\times 700$
$\therefore \mathit{r}=\sqrt{7\times 7\times 100}=70$ metre
∴ Circumference of circular field $=2\mathrm{\pi }\mathit{r}$ metre $=2\times \frac{22}{7}\times 70=440$ metre
∴ Total expenditure fencing = Rs. (440 × 1.2) = Rs. 528