Question

A door of length $$2\ m$$ and breadth $$1\ m$$ is fitted in a wall. The length of the wall is $$4.5\ m$$ and the breadth is $$3.6\ m.$$ Find the cost of white washing the wall, if the rate of white washing the wall is $$Rs.20$$ per $$m^2.$$

Answer 1

$$\text{Step-1: Finding the area for calculating the cost}$$

$$\text{From the given values,}$$

$$\text{Area of the wall including the door}$$ $$=length \times breadth$$

$$=4.5\times 3.6=16.2\: m^2$$

$$\text{Area of the door}$$ $$=2\times 1=2\: m^2$$

$$\text{Area of wall excluding door}$$ $$=16.2-2=14.2\: m^2$$

$$\textbf{Step-2: Finding the cost of white washing}$$

$$\text{The rate of white washing}$$ $$1\: m^2$$ $$\text{of the wall is}$$ $$Rs.\: 20$$

$$\text{The rate of white washing}$$ $$14.2\: m^2$$ $$\text{of the wall is}$$ $$=20\times 14.2=Rs.\: 284$$

$$\textbf{Hence , the rate of white washing the wall excluding the door is}$$ $$\mathbf{Rs.\: 284.}$$