Question

The cost of fencing a square lawn at Rs 14 per metre is Rs 2800. Find the cost of mowing the lawn at Rs 54 per 100 cm².

Answer 1

Given:
Cost of fencing = Rs 2800
Rate of fencing = Rs 14

Now,
Perimeter$=\frac{\mathrm{Total}\mathrm{cost}}{\mathrm{Rate}}=\frac{2800}{14}=200\mathrm{m}$

Because the lawn is square, its perimeter $\mathrm{is}4a,\mathrm{where}\mathit{}a\mathrm{is}\mathrm{the}\mathrm{side}\mathrm{of}\mathrm{the}\mathrm{square})$.
$\Rightarrow 4a=200\Rightarrow a=\frac{200}{4}=50\mathrm{m}$

Area of the lawn = ${\mathrm{Side}}^2={50}^2=2500{\mathrm{m}}^2$

Cost for mowing the lawn per 100 m²= Rs 54

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

Total cost for mowing the lawn per 2500 m²$=\frac{54}{100}\times 2500=\mathrm{Rs}1350$