1. The problem statement, all variables and given/known data i am asked to find the value of y in this question . I am not sure should i consider the atmospheric pressure acting on the mercury or not . 2. Relevant equations 3. The attempt at a solution i choose to consider the atmospheric pressure as 0 in this case . So , my working is 30000 + (1.5x820x9.81) + (5 x1000x9.81) =13600(9.81)y , where y = 0.68m , am i right ? btw , i am not very sure about whether the pressure of water is (5 x1000x9.81) or not , because the outlet is not at bottom of teh tank , can someone exp;lain pls ?