Question

The floor of a rectangular hall has a perimeter $250m$. If the cost of painting the four walls at the rate of $Rs.10per{m}^2$ is $Rs.15000$, find the height of the hall.
[Hint : Area of the four walls $=$ Lateral surface area.]

Answer 1

Let in rectangular hall,

length $=l$

breadth = $b$

height = $h$

It is given that, Perimeter of rectangular hall is $250m$.

$\Rightarrow 2(l+b)=250$

Since, the cost of painting the four walls at the rate of $Rs.10per{m}^2$ is $Rs.15000$.

Area of four walls $=2h(l+b)$

$\Rightarrow 2h(l+b)=\frac{Rs.15000}{Rs.10/m^2}$

$\Rightarrow h\left(2\right(l+b)=1500m^2$

$\Rightarrow h\times 250m=1500m^2$

$\Rightarrow h=\frac{1500m^2}{250m}$

$\Rightarrow h=6m$

Therefore, height of the wall is $6m$.