a wooden bookshelf has external dimensions as follows:
height=110 cm
depth=25 cm
breadth=85 cm
the thickness of the plank is 5 cm everywhere. the external faces are to be polished and the internal faces of the shelf are to be painted. if the rate of polishing is 20p. per cm^2 and the rate of painting is 10p. per cm^2 , find the total expenses of polishing and painting the surface of the bookshelf