A milk container of height 16 cm is made of metal sheet in the form of a frustum of a cone with radii of its lower and upper ends as 8 cm and 20 cm, respectively. Find the cost of milk at the rate of ₹22 per L which the container can hold.

Explanation

Given that,height of milk container (h) = 16 cm
Radius of lower end of milk container (r) = 8 cm
and radius of upper end of milk container (R) = 20 cm

`therefore` Volume of the milk container made of metal sheet in the form of a frustum of a cone
`=(pih)/(3) (R^(2) + r^(2)+ Rr)`
`= (22)/(7) xx (16)/(3) [(20)^(2)+ (8)^(2) + 20 xx8]`
`= (22 xx 16 )/(21) (400 + +64+160)`
` (22 xx 16 xx 624)/(21) = (219648)/(21),,[therefore 1 L = 1000 cm^(3)]`
`= 10459.42 cm^(3) = 10.45942 L`
So, volume of the milk container is `10459.42 cm^(3)`.
`because` Cost of 1 L milk = ₹22
`because` Cost of 10.45942 L milk `= 22 xx 10.45942= ₹ 230.12`
Hence, the required cost of milk is ₹230.12