1. The problem statement, all variables and given/known data in the previous therad https://www.physicsforums.com/threads/flow-in-branch-pipe.866194/ (post #14) , i was told that water can flow in one direction only in a netwrok of pipes . However , in the notes uploaded here , the author stated that when P is below surface of B , then water must be out of B and Q1 + Q2 = Q3 ? 2. Relevant equations 3. The attempt at a solution IMO , it should be Q2 = Q1 + Q3 , since i was told that water can only flow in 1 direction , am i right ?