The decorative block shown in the figure is made of two solids - a cube and a hemisphere. The base of the block is a cube with edge $5 \, cm$,and the hemisphere fixed on the top has a diameter of $4.2 \, cm$. Find the total surface area of the block. (in $cm^2$) (Take $\pi = \frac{22}{7}$)

$A$ toy is in the form of a cone of radius $3.5 \, cm$ mounted on a hemisphere of the same radius. The total height of the toy is $15.5 \, cm$. Find the total surface area of the toy (in $cm^2$). $\left[ \text{Use } \pi = \frac{22}{7} \right]$

Shanta runs an industry in a shed which is in the shape of a cuboid surmounted by a half cylinder (see figure). If the base of the shed is of dimension $7\,m \times 15\,m,$ and the height of the cuboidal portion is $8\,m,$ find the volume of air that the shed can hold. Further,suppose the machinery in the shed occupies a total space of $300\,m^3,$ and there are $20$ workers,each of whom occupy about $0.08\,m^3$ space on an average. Then,how much air is in the shed? (in $m^3$) (Take $\pi = \frac{22}{7}$)

$A$ metallic sphere of radius $4.2 \, cm$ is melted and recast into the shape of a cylinder of radius $6 \, cm$. Find the height of the cylinder. (in $cm$) [Take $\pi = \frac{22}{7}$]

Metallic spheres of radii $6 \, cm$,$8 \, cm$,and $10 \, cm$,respectively,are melted to form a single solid sphere. Find the radius of the resulting sphere (in $cm$).

Selvi's house has an overhead tank in the shape of a cylinder. This is filled by pumping water from a sump (an underground tank) which is in the shape of a cuboid. The sump has dimensions $1.57 \, m \times 1.44 \, m \times 95 \, cm$. The overhead tank has a radius of $60 \, cm$ and a height of $95 \, cm$. Find the height of the water left in the sump after the overhead tank has been completely filled with water from the sump which had been full. Compare the capacity of the tank with that of the sump. (Use $\pi = 3.14$)