The internal measures of a cuboidal room are with length as 12 m, breadth as 8 m and height as 10 m. The total cost (in ₹) of white washing all four walls of the room and also the ceiling of the room,if the cost of whitewashing is ₹25 per m² is :

12,400

We know that,

Lateral surface area = 2(l + b)h

Area of the rectangle = l × b

We have,

Length of the room = 12 m

Breadth = 8 m

Height = 10 m

Cost of whitewash = 25 per m²

Area of ceiling = 12 × 8 = 96

Area of walls = 2 × 10 × (12 + 8) = 400

Total cost of whitewash = 25 ×  (400 + 96) = 12400