The dimensions of a room are 10 m x 7m x 5 m. There are 2 doors and 3 windows in the room. The dimensions of the doors are 1 m x 3 m. One window is of size 2 m x 1.5 m and the other two windows are of size 1 m x 1.5 m. The cost of painting the walls at ₹3 per m$$^2$$ is ........

The given dimensions of the room are 10 m x 7m x 5 m

l x b x h = 10 x 7 x 5

We know the area of walls is = 2(lh + bh) = 2(10*5 + 7*5) 

Hence, the area of the walls = 170 sq m

We have to subtract the area of doors and the windows to get the paintable area

Area of both doors = 2*(1 x 3) = 6 sq m

Area of one window = 2 x 1.5 = 3 sq m

Area of other two windows = 2*(1 x 1.5) = 3 sq m

So, the paintable area = 170 - (6+3+3) = 158 sq m

Given the cost to paint is ₹3 per sq m

So, the total cost is $$158\times3=474$$