Question

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 $m^2$ is

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Answer 1

The surface of the walls constitute the lateral surface area.

Lateral surface area = 2(bh+hl) = 2(52 + 58.5) = 221$m^2$

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 $m^2$

Cost of White Washing = 215 × 6.4 = Rs.1376