Here water level is kept same all the time. So, the amount of water remove from the hole put in the tank the top to keep the water level same.

$$ \therefore $$   Inflow volume role = outflow volume

$$ \Rightarrow $$   $${{0.74} \over {60}} = Av$$

$$ \Rightarrow $$   $${{0.74} \over {60}} = \pi {r^2}\left( {\sqrt {2gh} } \right)$$

$$ \Rightarrow $$   $${{0.74} \over {60}} = \pi \left( {4 \times {{10}^{ - 4}}} \right) \times \sqrt {2gh} $$

$$ \Rightarrow $$   $$\sqrt {2gh} $$ = $${{740} \over {24\pi }}$$

$$ \Rightarrow $$   2gh = $${{740 \times 740} \over {24 \times 24 \times {\pi ^2}}}$$

$$ \Rightarrow $$   h = 4.8 m