Question

The cost of harvesting a square field at the rate of Rs 180 per hectare is Rs 1620. Find the cost of putting a fence around it at the rate of Rs 6.75 per metre.

Answer 1

Let the side of the field be $l$ m.

Cost of harvesting$=\mathrm{Rs}1620$

$$\begin{gathered} \Rightarrow 180\times \mathrm{Area}\mathrm{of}\mathrm{the}\mathrm{square}=1620 \\ \Rightarrow 180l^2=1620 \end{gathered}$$

$$\begin{gathered} \Rightarrow l^2=\frac{1620}{180} \\ \Rightarrow l^2=9\mathrm{hectares} \\ \mathrm{Area}\mathrm{of}\mathrm{the}\mathrm{field}=9\mathrm{hectares}=90000{\mathrm{m}}^2 \\ \Rightarrow l=300\mathrm{m} \\ \mathrm{Perimeter}\mathrm{of}\mathrm{the}\mathrm{square}\mathrm{field}=4\times 300=1200\mathrm{m} \\ \therefore \mathrm{Cost}\mathrm{of}\mathrm{putting}\mathrm{up}\mathrm{the}\mathrm{fence}=1200\times 6.75=\mathrm{Rs}8100 \end{gathered}$$