A company sells biscuits. For packing purpose they are using cuboidal boxes: 
box A  3 cm x 8 cm x 20 cm,  box B  4 cm x 12 cm x 10 cm. What size of the box will be economical for the company? why? Can you suggest any other size (dimensions) which has the same volume but is more economical than these?

Given a cylindrical tank, in which situation will you find surface area and in which situation volume.
(a)   To find how much it can hold.
(b)   Number of cement bags required to plaster it.
(c)    To find the number of smaller tanks that can be filled with water from it.

A milk tank is in the form of cylinder whose radius is 1.5 m and length is 7 m. Find the quantity of milk in litres that can be stored in the tank?

 If each of a cube is doubled,
(i) How many times will its surface area increase?
(ii) How many times will its volume increase?