21 glass spheres, each of radius 2 cm

Solution:

It is given that 21 glass spheres each of radius 2 cm are packed in a cuboidal box of inner dimensions and then filled with water.

We have to find the volume of water.

Radius of glass sphere r

Volume of a glass sphere $=\frac{4}{3} \pi r^{3}$

Volume of 21 glass spheres $=21 \times \frac{4}{3} \times \frac{22}{7} \times 2^{3}$

$=21 \times \frac{4}{3} \times \frac{22}{7} \times 8$

$=704 \mathrm{~cm}^{3}$

Length of cuboidal box 

Breadth of cuboidal box 

Height of cuboidal box 

Volume of the cuboidal box $=$ length $\times$ breadth $\times$ height

$=16 \times 8 \times 8$

 

$=1024 \mathrm{~cm}^{3}$

Volume of water = Volume of cuboidal box − Volume of glass spheres

$=1024-704$

$=320 \mathrm{~cm}^{3}$