# Q : 2      The length, breadth and height of a room are $\small 5\hspace {1mm}m$, $\small 4\hspace {1mm}m$ and $\small 3\hspace {1mm}m$ respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of $\small Rs \hspace {1mm} 7.50$   per $\small m^2$.

N Nehul

Given,

Dimensions of the room = $5\ m\times4\ m\times3\ m$

Required area to be whitewashed = Area of the walls + Area of the ceiling

$2(lh+bh) + lb$

$\\ = 2(5\times4+4\times3)+ 5\times4 \\ = 2(32)+20 = 74\ m^2$
Cost of white-washing per $\small m^2$ area = $\small Rs \hspace {1mm} 7.50$
Cost of white-washing $74\ m^2$area = $Rs (74 \times 7.50)$
$= Rs.\ 555$

Therefore, the required cost of whitewashing the walls of the room and the ceiling is $Rs.\ 555$

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