Question

a rectangular room of dimensions 8 m into 6 into 3 m is to be painted if it costs rupees 16 per metre square find the cost of painting the walls

Answer 1

Hey Mate !!!

So, according to the question, we are painting the walls of a rectangular room. The rectangular room's 3D shape is CUBOID.

i.e. we paint four sides of the room.

Lateral surface area (area of four sides) of solid cuboid = 2h( l + b)

According to the question,

let us assume that:

length, l = 8m

breadth, b = 6m

height, h = 3m

Lateral surface area (area of four sides) of solid cuboid = 2 (3)( 8 + 6)

                                                                                                = 6 X 14 = 84 m²

Rate of Painting the Wall =₹16 per m²

i.e. cost of painting the wall = ₹16 X 84 = ₹ 1344

Cheers !!!!

Now the point comes, how to solve such questions??

It is pretty easy !!!

Steps :

• first you need to find out how many sides of the walls are painted.  either there would be 5 walls to be painted (four sides and ceiling) or only four sides. It would be mentioned in the question
• find the total area that has to be painted.
• rate would also be given in the question.
• multiply this rate with the total area of the painted region.

DONE !!!!