Question

The length,breadth and height of a room is 5 m, 4 m and 3 m. The cost of whitewashing its four walls at the rate of Rs.7.50 per sq.m is?

Answer 1

Answer:

length * breadth *height

5 * 4 * 3

60$m^{2}$

60 *7.50

450 rupees

Answer 2

Given :

• The length, breadth and height of a room is 5 m, 4 m and 3 m.

To find :

• The cost of whitewashing its four walls at the rate of Rs.7.50 per m² .

Solution :

· Length = 5 m

· Breadth = 4 m

· Height = 3 m

⭑ Area of 4 walls = LSA of the cuboidal room.

⭑ LSA of cuboid = 2(l + b) × h

So according.to quéstion

⇒ Area of 4 walls = 2(5 + 4) × 3

⇒ Area of 4 walls = 2 × 9 × 3

⇒ Area of 4 walls = 54 m²

⭑ Rate of whitewashing = Rs. 7.50/m²

⇒ Cost of whitewashing = Area of 4 walls × Rate

⇒ Cost of whitewashing = 54 × 7.50

⇒ Cost of whitewashing = Rs. 405

∴ Cost of whitewashing its 4 walls = Rs. 405