A venturi meter (venturi coefficient, $C_{v} = 0.98$) is connected to a pipe of inner diameter $50$ $\text{mm}$. Water (density $1000\:kg\:m^{-3}$) is flowing through the pipe. The pressure-drop measured across the venturi meter is $50$ $\text{kPa}$. If the venturi throat diameter is $20$ $\text{mm}$, the estimated flow rate of water is ___________ $\times 10^{-3}\:m^{3}\:s^{-1}$ (rounded off to two decimal places)