Question

A swimming pool is 20 m long 15 m wide and 3 m deep. Find the cost of repairing the floor and wall at the rate of Rs 25 per square metre.

Answer 1

$$\begin{gathered} \mathrm{Length}\mathrm{of}\mathrm{the}\mathrm{swimming}\mathrm{pool}=20\mathrm{m} \\ \mathrm{Breadth}=15\mathrm{m} \\ \mathrm{Height}=3\mathrm{m} \\ \mathrm{Now},\mathrm{surface}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{floor}\mathrm{and}\mathrm{all}\mathrm{four}\mathrm{walls}\mathrm{of}\mathrm{the}\mathrm{pool}=(\mathrm{length}\times \mathrm{breadth})+2\times (\mathrm{breadth}\times \mathrm{height}+\mathrm{length}\times \mathrm{height}) \\ =(20\times 15)+2\times (15\times 3+20\times 3) \\ =300+2\times (45+60) \\ =300+210 \\ =510{\mathrm{m}}^2 \\ \mathrm{The}\mathrm{cost}\mathrm{of}\mathrm{repairing}\mathrm{the}\mathrm{floor}\mathrm{and}\mathrm{the}\mathrm{walls}\mathrm{is}\mathrm{Rs}25/{\mathrm{m}}^2. \\ \therefore \mathrm{The}\mathrm{total}\mathrm{cost}\mathrm{of}\mathrm{repairing}510{\mathrm{m}}^2\mathrm{area}=510\times 25=\mathrm{Rs}12750 \end{gathered}$$