A company plans to manufacture a container having the shape of a right circular cylinder, open at the top, and having a capacity of 24 π cubic inches. If the cost of the material for the bottom is  $0.30  per square inch and that for the curved sides is  $0.10  per square inch, express the total cost C, in dollars, of the material as a function of the radius r of the base of the container.   The volume V of a right circular cylinder of radius r and height h is V=pi r^2 h; the surface area S of this same open cylinder is S= pi r^2 + 2 pi rh.