Question

The length , breadth and height of a room are 9m , 8m and 7m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of Rs 6.50 per m^2

Answer 1

Answer:

Total cost of whitewashing is 2,088 rupees.

Given-:

Dimensions of the rectangle are :

Length(l) = 8.5m

Breath(b)= 7m

Height(h) = 6.5m

As for whitewashing the four walls we need to find the surface area.

Area of the four walls or the curved surface area of rectangle = 2*h*(l+b)

=> 2*6.5*(8.5 + 7)

=> 2*6.5*15.5

=> 201.5 m²

And for the area of the ceiling we need to find the area of only one rectangular side i.e (l*b).

=> Area = (l*b)

=> Area = 8.5*7

=> Area = 59.5m²

Hence-:

Total area of the four walls of room and the ceiling = (201.5 + 59.5)m² = 261m²

We have-:

Cost of whitewashing 1 m² = 8 rupees

So cost for the whitewashing 261 m² will be as

=> 261*8 rupees

=> 2,088 rupees

Therefore-:

Total 2088 rupees will be required for the whitewashing 261 m².

Answer 2

Answer:

Step-by-step explanation:

We have to find the area of 4 walls and a ceiling, so we'll use the formula of lateral surface area of cuboid.

Lateral surface area of cuboid=2(LB+BH+HL)

Area of ceiling=LxB

ATQ,

Area of room except floor=area of 4 walls +area of ceiling

Or,area= 2(LB+BH+HL)+LB

or,area=2{(9*8)+(8*7)+(7*9)}+(9*8)

or,area=2(72+56+63)+(72)

or,area=(2* 191)+72

or,area=382+72

or,area=454 m^2

now,

Cost of white washing=(454*6.5)

or,cost=rs.2951