CMAT 2019 Solved Question Paper

let the length of the halls be 'a' and 'a+1' m respectively and height of the halls be 'h' m.
Area of 4 walls of first square hall $\left({\mathit{A}}_1\right)=4\times \mathit{a}\times \mathit{h}{\mathit{m}}^2$
Given, cost of painting is Rs. 5 per sq.m
⇒ cost of painting 4 walls of the first square hall $={\mathit{A}}_1\times 5=20\times \mathit{a}\times \mathit{h}$.
Given that this cost of painting = Rs. 6000
$20\times \mathit{a}\times \mathit{h}=6000$...........(1)
Similarly,Area of 4 walls of second square hall $\left({\mathit{A}}_2\right)=4\times \left(\mathit{a}+1\right)\times \mathit{h}{\mathit{m}}^2$
⇒ cost of painting 4 walls of the second square hall $={\mathit{A}}_2\times 5=4\times \left(\mathit{a}+1\right)\times \mathit{h}\times 5$
$=\mathrm{Rs}.20+\left(\mathit{a}+1\right)\times \mathit{h}$
Given that this cost of painting = Rs. 6100
$20\times \left(\mathit{a}+1\right)\times \mathit{h}=6100$............(2)
Dividing (2) with (1), we get
$\frac{\mathit{a}+1}{\mathit{a}}=\frac{6100}{6000}$
$\mathit{a}=60$
Substituting this value in equation (1), we get
$20\times 60\times \mathit{h}=6000$
$\mathit{h}=5\mathit{m}$.
So, the height of the two walls is 5 m.