The dimensions of a room are $12.5\ m$ by $9\ m$ by $7\ m$. There are 2 doors and 4 windows in the room; each door measures $2.5\ m$ by $1.2\ m$ and each window $1.5\ m$ by $1\ m$. Find the cost of painting the walls at $Rs.\ 3.50$ per square metre.

Given:

The dimensions of a room are $12.5\ m$ by $9\ m$ by $7\ m$. There are 2 doors and 4 windows in the room; each door measures $2.5\ m$ by $1.2\ m$ and each window $1.5\ m$ by $1\ m$. 

To do:

We have to find the cost of painting the walls at $Rs.\ 3.50$ per square metre.

Solution:

Length of the room $(l) = 12.5\ m$

Breadth of the room $(b) = 9\ m$

Height of the room $(h) = 7\ m$

Therefore,

Total area of walls $= 2h(l + b)$

$= 2 \times 7(12.5 + 9)$

$= 14 \times 21.5$

$= 301\ m^2$

Area of two doors of $2.5\ m \times 1.2\ m = 2 \times 2.5 \times 1.2$

$= 6\ m^2$

Area of four window of $1.5\ m \times 1\ m$

$= 4 \times 1.5 \times 1$

$= 6\ m^2$

Therefore,

Remaining area of the walls $= 301 - (6 + 6)$

$= 301 - 12$

$= 289\ m^2$

Rate of painting the walls $= Rs.\ 3.50$ per $m^2$

Total cost of painting $= 289 \times 3.50$

$= Rs.\ 1011.50$

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Updated on: 10-Oct-2022

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