Question

A square room is 15 m long and 6 m high. It contains three square windows each of
2 m long and a door of size 1.5 m x 5 m. Find the total cost of plastering and colouring
its walls and ceiling at Rs 30 per sq. metre and Rs 20 per sq. metre respectively.​

Answer 1

Answer:

Step-by-step explanation:

The cost of painting it's four walls and ceiling at Rs. 5.30 per sq m is Rs. 2253.34.

Step-by-step explanation:

Step 1:

The length of the room, l = 15 m

The breadth of the room, b = 12 m

The height of the room, h = 5 m

∴ Area of the ceiling of the room = l * b = 15 * 12 = 180 m² ….. (i)

And,

∴ Area of the 4 walls of the room including the doors and windows = 2h[l+b] = 2 * 5 * [15+12] = 270 m² …… (ii)

Step 2:

It is given that,

Dimensions of three doors = 2 m x 1.5 m each

So, Area of 3 doors = 3 * [l*b] = 3 * 2 * 1.5 = 9 m² ….. (iii)

And,

Dimensions of 4 windows = 2.2 m x 1.8 m each

So, Area of 4 windows = 4 * [l*b] = 4 * 2.2 * 1.8 = 15.84 m² ….. (iv)

Step 3:

From (i), (ii), (iii) & (iv), we get

Area of 4 walls and ceiling of the room excluding the doors and windows is,

= [Area of the walls of the room including the doors and windows] + [Area of the ceiling of the room]– [Area of 3 doors] – [Area of 4 windows]

= 270 + 180 – 9 – 15.84

= 425.16 m²

The cost of painting the four walls and ceiling of the room is given as = Rs 5.30 per m²

Thus,

The cost of painting the four walls and ceiling of the room (excluding the doors and windows) is,

= 425.16 m² * Rs. 5.30

= Rs. 2253.34