Q. 24.4( 440 Votes )

# 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}.

Answer :

**Given:** Length = 5m, Breadth = 4m, and Height = 3m**Diagram:**

It can be observed that four walls and the ceiling of the room are to be whitewashed.

The floor of the room is not to be white-washed

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

= 2lh + 2bh + 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**

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