1. The problem statement, all variables and given/known data Water (of density 1000 kg/m^3) flows into a cylindrical tank through two pipes at mass flow rates of 6 kg/sec and 10 kg/sec respectively, and leaves the tank via a circular outlet pipe of 20 cm diameter. If the water level in the tank is to remain constant, calculate the average flow velocity in the outlet pipe. 2. Relevant equations Q1 + Q2 = Q3 ---> A1*u1 + A2*u2 = A3*u3 3. The attempt at a solution I'm really tempted to just say, well the water coming in is 10 kg/sec and 6 kg/sec so the water exiting must be 16 kg/sec. I'm not sure you can do that though, but there are too many unknowns! You have A3, but not A1 or A2. You have u1 and u2, but not u3 (what you're solving for). A1(6 kg/sec) + A2 (10 kg/sec) = pi*0.2m^2*u3 Can anyone steer me in the right direction?