Answer
a) $8.3\frac{L}{s}$
Work Step by Step
Here we are working with potential energy:
The potential work is: $W_{p}=mgh$
And the potential power is: $P_{p}=\frac{W_{p}}{t}=\frac{mgh}{t}=\rho Qgh$
Solving for $Q$:
$Q=\frac{P_{p}}{\rho gh}=\frac{2000W}{(0.820\frac{kg}{L}*\frac{1000L}{1m^3})*9.81\frac{m}{s^2}30m}=0.0083\frac{m^3}{s}*\frac{1000L}{1m^3}=8.3\frac{L}{s}$