Question

A milk container of height 16 cm is made of metal sheet in the form of 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 Rs.44 per litre which the container can hold.

Answer 1

Given,

A milk container of the form of frustum of a cone

The radius of the lower end (r₁) = 8 cm

The radius of the upper end (r₂) = 20 cm

Let h be its height, h = 16 cm

Then, the capacity of the container = Volume of frustum of the cone

= 1/3 π(r₂² + r₁² + r₁ r₂ )h

= 1/3 π(20² + 8² + (20) (8) ) x 16

= 10459.42 cm³

= 10.46 litres

Now, given that cost of 1 litre of milk = Rs 44

Then the cost of 10.46 litres of milk = Rs (44 x 10.46) = Rs 460.24