#### Question

The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of Rs 7.50 per m^{2}.

#### Solution

It is given that

Length (*l*) of room = 5 m

Breadth (*b*) of room = 4 m

Height (*h*) of room = 3 m

It can be observed that four walls and the ceiling of the room are to be white-washed. The floor of the room is not to be white-washed.

Area to be white-washed = Area of walls + Area of ceiling of room

= 2*lh* + 2*bh* + *lb*

= [2 × 5 × 3 + 2 × 4 × 3 + 5 × 4] m^{2}

= (30 + 24 + 20) m^{2}

= 74 m^{2}

Cost of white-washing per m^{2} area = Rs 7.50

Cost of white-washing 74 m^{2} area = Rs (74 × 7.50)

= Rs 555

Is there an error in this question or solution?

Solution The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of Rs 7.50 per m^2. Concept: Surface Area of a Cuboid and a Cube.