Question

The dimensions of a room are (9 m × 8 m × 6.5 m). It has one door of dimensions (2 m × 1.5 m) and two windows, each of dimensions (1.5 m × 1 m). Find the cost of whitewashing the walls at Rs. 6.40 per square meter.​

Answer 1

Solution:

Length of a room = 9 m

Breadth of a room = 8 m

Height of a room = 6.5 m

∴ Area of 4 walls = Lateral Surface Area

Lateral surface area of the room

= 2(l + b) × h

= [2(9 + 8) × 6.5]

= (2 × 17 × 6.5)

= 221 m²

∴ Area not white washed

= (Area of One Door) + (Area of 2 Windows)

= (2 × 1.5) + (2 × 1.5 × 1)

= 3 + 3

= 6 m²

∴ Area whitewashed

= (221 – 6)

= 215 m²

∴ Cost of Whitewashing the Walls at the Rate of Rs.6.40 per Square Meter

= Rs. (6.40 × 215)

= Rs. 1376

Hope it Helps !!!!

Answer 2

Answer:-

Rs. 1376

Explanation:-

Given

Dimensions of Room

length = 9m

breadth = 8m

height = 6.5m

Dimensions of door

length = 2m

breadth = 1.5m

Dimensions of the windows

length = 1.5m

breadth = 1m

Cost of white washing is Rs. 6.40 /m²

To Find

Cost of white washing the walks

Solution

LSA of the room LSA(R):

$\boxed{lateral \: surface \: area \: of\: a \:cuboid = 2h(l+b)}$

LSA(R)= 2(6.5)[9+8]

LSA(R)= 13(17)

LSA(R) = 221 m²

Area covered by door A(D) :

$Length × Breadth$

A(D) = 2 × 1.5

A(D) = 3m²

Area covered by the two windows A(W) :

A(W) = 2[1.5 × 1)

A(W) = 2(1.5)

A(W) = 3m²

Area to be white washed =

LSA(R) - A(D) - A(W)

= 221 - 3 - 3

= 221-6

= 215m²

Cost for white washing 215m²

= 215 × 6.40

= 1376

Hence, Rs.1376 is the cost.. which is required to paint the walls