CBSE Class 10 Maths (Standard) 2019 · Paper 30/4/2 · Question 30

A container opened at the top and made up of a metal sheet, is in the form of a frustum of a cone of height $16$ cm with radii of its lower and upper ends as $8$ cm and $20$ cm respectively. Find the cost of milk which can completely fill the container, at the rate of ₹ $50$ per litre. Also find the cost of metal sheet used to make the container, if it costs ₹ $10$ per $100$ cm${}^2$. (Take $\pi =3.14$)