A container, opened from the top and made up of a metal sheet 1 is in the form of a frustum of a cone of height 16 cm with radii of its lower and upper ends as 8cm and 20cm respectively. Find the cost of the milk. Which can completely fill the container, at the rate of Rs. 20/- per litre? Also find the cost of metal sheet used to make the container, if it costs Rs. 8/- per 100cm2.