The dimensions of a room are 9m × 8m × 6.5m. It has one door of dimensions 2m×1.5m and two windows each of dimensions 1.5m×1m. Find the cost of white washing the walls at Rs. 6.40 per m2 is
The surface of the walls constitute the lateral surface area.
Lateral surface area = 2(bh+hl) = 2(52 + 58.5) = 221m2
We have to subtract the areas of the door and the windows.
So, the area that is to be white washed = 221 - (2 × 1.5) - 2(1.5 ×1) = 215 m2
Cost of White Washing = 215 × 6.4 = Rs.1376