Hello! 1. The problem statement, all variables and given/known data I need to find the instantaneous height of a liquid during the simultaneous filling and emptying (through a hole) of a cylinder. I have varying Qin at incremental time of 1 sec. with cylinder area=5 cm and orifice area=0.5 cm. 2. Relevant equations Torricelli's theorem Continuity equation 3. The attempt at a solution 1) Used V=Qt to find volume for each flow rate. 2) Calculated H=V/A. 3) Used torricelli's theorem to calculate Qout. But this doesn't seem to me like the correct modeling of the problem and am stuck on how to go about it.