The front compound wall of a house is decorated by wooden spheres of diameter 21 cm, placed on small supports as shown in Fig.
.Eight such spheres are used for this purpose, and are to be painted silver. Each support is a cylinder of radius 1.5 cm and height 7 cm and Is to be painted black. Find the cost of paint required if silver paint costs 25 paise per `cm^2` and black paint costs 5 paise per `cm^2`.