The dimensions of a room are 10 m x 7 m x 5 m. There are 2 doors and 3 windows in the roorrf. 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 Rs. 3 per m^2 is :
