Question

If the dimension of a rectangular room are 10m x 12m x 9m, then the cost of painting its four walls at the rate of Rs.8 per m2 is

Answer 1

Step-by-step explanation:

area of 4 walls=2(bh+hl)

2(108+90)

2(198)

area of 4 walls=396

cost of painting=rs 3168

Answer 2

The cost of painting of four walls of the rectangular room is Rs. 3168.

If the dimension of a rectangular room are 10m × 12 m × 9m.

We have to find the cost of painting its four walls at the rate of Rs. 8 per m².

We know, there are six face of a rectangular room. here ceiling and floor of the room are not being painted.

∴ the area of remaining four walls = 2(l + b)h

where l is length , b is width and h is height of rectangular room.

here,

• l = 10 m
• b = 12m
• h = 9 m

the area of four walls = 2(10 + 12) × 9

= 2(22m) × 9m

= 44 × 9 m²

= 396 m²

∵ The rate at which walls are being painted is 8 Rs./m²

∴ total cost = rate × area of four walls

= 8 × 396

= 3168 Rs.

Therefore the cost of painting of four walls of the rectangular room is Rs. 3168.