Radius (r1) of upper end of container = 20 cm
Radius (r2) of lower end of container = 8 cm
Height (h) of container = 16 cm
Slant height (l) of frustum =
Capacity of container = Volume of frustum
Cost of 1 litre milk = Rs 20
Cost of 10.45 litre milk = 10.45 × 20
= Rs 209
Area of metal sheet used to make the container
= π (20 + 8) 20 + π (8)2
= 560 π + 64 π = 624 π cm2
Cost of 100 cm2 metal sheet = Rs 8
Cost of 624π cm2 metal sheet = (624 x 3.14 x 8)/100
=156.75
Therefore, the cost of the milk which can completely fill the container is
Rs 209 and the cost of metal sheet used to make the container is Rs 156.75.