A solid is in the shape of a right-circular cone surmounted on a hemisphere, the radius of each of them being $3.5 cm$ and the total height of the solid is $9.5 cm$. Find the volume of the solid.

The diameters of the lower and upper ends of a bucket in the form of frustum of a cone are $10 \mathrm{cm}$ and $30 \mathrm{cm}$ respectively. If its height is $24 \mathrm{cm}$, find

(i) the area of the metal sheet used to make the bucket.

(ii) Why we should avoid the bucket made by ordinary plastic? [Use $\mathrm{\pi }=3.14$]

A bucket in the form of a frustum of a cone of height $30 \mathrm{cm}$ with radii of its lower and upper ends as $10 \mathrm{cm}$ and $20 \mathrm{cm}$, respectively. Find the capacity of the bucket. Also find the cost of milk which can completely fill the bucket at the rate of $₹40$ per litre. $\left(\mathrm{Use} \mathrm{\pi }=\frac{22}{7}\right)$