Two cones with the same base radius $8\, cm$ and height $15\, cm$ are joined together along their bases. Find the surface area of the shape so formed. (in $cm^2$)

$A$ cubical ice cream brick of edge $22 \, cm$ is to be distributed among some children by filling ice cream cones of radius $2 \, cm$ and height $7 \, cm$ up to its brim. How many children will get the ice cream cones?

$A$ cylinder is closed at both the ends by $18\, cm$ high cones. The radius of the cylinder is $7\, cm$ and the total height of the solid is $64\, cm$. Find the volume of this solid (in $cm^3$).

Two identical cubes each of volume $64 \, cm^{3}$ are joined together end to end. What is the surface area of the resulting cuboid? (in $cm^{2}$)

For the science fair,a student prepared a model in the shape of a cylinder with radius $10 \,cm$ and height $40 \,cm$,closed at both ends by cones with slant height $26 \,cm$. How many litres of water can it contain?

$A$ cylindrical tank is closed at both the ends by hemispheres. Its radius is $2.1 \,m$ and the total height is $9.2 \,m$. How many litres of petrol can it contain?