Question

The cost of painting the walls of a room at the rate of $Rs.1.35$ per square metre is $Rs.340.20$ and the cost of matting the floor at the rate of $Rs.0.85$ per $c{m}^2$ is $Rs.91.80$. If the length of the room is $12m$, then what is the height of the room?

• A. $9m$
  
• B. $11m$
  
• C. $12m$
  
• D. $6m$
  

Answer 1

The correct option is D $6m$

Area of four walls of a room $=2(l+b)h=\frac{340.20}{1.35}=252m^2$
Also, $l\times b=\frac{91.8}{0.85}=108m^2$

$\Rightarrow b=\frac{108}{12}m=9m$
$\Rightarrow 2(12+9)\times h=252$

$\Rightarrow h=\frac{252}{42}=6m$