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.

Answer 1

Here, l = 5 m, b = 4 m, h = 3 m 

Surface area of the walls of the room and the ceiling 

= 2h (l + b) + lb 

= [2 × 3 (5 + 4) + 5 × 4] m² 

= (6 × 9 + 20) m² = 74 m² 

Cost of white washing = Rs 7.50 per m² 

∴ total cost of white washing the walls and the ceiling of the room 

= Rs 74 × 7.50 = Rs 555 Ans.