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

Answer: Option A

$$l$$ = 12 cm
b = 8 cm
h = 10 cm
Cost = Rs. 25/m²
Area of 4 walls = 2($$l$$ + b) × h
= 2(12 + 8) × 10
= 400 m²
Area of roof = 12 × 8 = 96 m²
Total Area = 400 + 96 = 496
Cost = 496 × 25 = Rs. 12400