A cuboidal shaped water tank, 2.1 m long and 1.5 m broad is half filled with water. If 630 litres more water is poured into tank, the water level will rise

$$\eqalign{ & 2.1{\text{ m}} \times 1.5{\text{ m}} \times h = 630{\text{ lt}} \cr & \frac{{21}}{{10}}{\text{m}} \times \frac{{15}}{{10}}{\text{m}} \times h = \frac{{630}}{{1000}}{{\text{m}}^3} \cr} $$
\[\left[ \begin{gathered} \because 1\,{{\text{m}}^3} = 1000{\text{ lt}} \hfill \\ {\text{1000 c}}{{\text{m}}^3} = 1{\text{ lt}} \hfill \\ \end{gathered} \right]\]
$$h = \frac{1}{5}{\text{m}} = 0.20{\text{ metre}}$$