Question

The cost of fencing a square lawn at Rs 14 per metre is Rs 28000. Find the cost of mowing the lawn at Rs 54 per 100 m².

Answer 1

Cost of fencing the lawn = Rs 28000
Let l be the length of each side of the lawn. Then, the perimeter is 4l.
We know:
$$\begin{gathered} \mathrm{Cost}=\mathrm{Rate}\times \mathrm{Perimeter} \\ \Rightarrow 28000=14\times 4\mathrm{l} \end{gathered}$$

$$\begin{gathered} \Rightarrow 28000=56l \\ Or, \\ l=\frac{28000}{56}=500\mathrm{m} \end{gathered}$$

Area of the square lawn$=500\times 500=250000{\mathrm{m}}^2$

Cost of mowing 100 m² of the lawn = Rs 54
Cost of mowing 1 m² of the lawn$=\mathrm{Rs}\frac{54}{100}$


∴ Cost of mowing 250000 m² of the lawn$=\frac{250000\times 54}{100}=\mathrm{Rs}135000$