$A$ child is playing with building blocks, which are in the shape of cubes, and has built a structure as shown in the figure. If the edge of each cube is $3 \, cm$, find the volume of the structure built by the child. (in $cm^3$)

$A$ soft drink is available in two packs: $(i)$ a tin can with a rectangular base of length $5 \, cm$ and width $4 \, cm$ having a height of $15 \, cm$,and $(ii)$ a plastic cylinder with a circular base of diameter $7 \, cm$ and height $10 \, cm$. Which container has greater capacity and by how much (in $, cm^3$)?

$A$ hemispherical tank is made up of an iron sheet $1 \,cm$ thick. If the inner radius is $1 \,m$,then find the volume of the iron used to make the tank. (in $,m^3$)

Find the surface area of a sphere of radius $14 \, cm$.
Assume $\pi = \frac{22}{7}$. (in $, cm^2$)

$A$ river $3 \,m$ deep and $40 \,m$ wide is flowing at the rate of $2 \,km$ per hour. How much water will fall into the sea in a minute (in $,m^3$)?

Twenty-seven solid iron spheres,each of radius $r$ and surface area $S$,are melted to form a single sphere with surface area $S'$. Find the ratio of $S$ to $S'$.