Power of a water pump is 2 kW.  If $\mathrm{g}=10\mathrm{m}/{\sec }^2$, the amount of water it can raise in one minute to a height of 10 m is (in litre)

$\mathrm{P}=\frac{\mathrm{mgh}}{\mathrm{t}} \Rightarrow \mathrm{m}=\frac{\mathrm{p}\times \mathrm{t}}{\mathrm{gh}}=\frac{2\times {10}^3\times 60}{10\times 10}=1200\mathrm{kg}$

As volume = $\frac{\text{mass}}{\text{density}}\Rightarrow \mathrm{v}=\frac{1200\mathrm{kg}}{{10}^3\mathrm{kg}\text{}/\text{}{\mathrm{m}}^3}=1.2{\mathrm{m}}^3$  
Volume =  $1.2{\mathrm{m}}^3=1.2\times {10}^3\mathrm{litre}=1200\mathrm{litre}$