1. The problem statement, all variables and given/known data A thin uniform circular tube is kept in a vertical plane. Equal volumes of (The liquids subtend a right angle at the centre) two non miscible liquids whose densities are a and b respectively fill half of the tube as shown. (The diagram depicts a>b) In equilibrium the radius passing through the interface makes an angle of 30 degrees with the vertical. The ratio of densities a/b is equal to. 2. Relevant equations The basic equations of fluid mechanics given in any introductory course. 3. The attempt at a solution I tried equating the weights on both the side as it must be necessary condition for the equilibrium. Doing so I have obtained the answer as 3. The answer given in the text is 3.732. Where is the flaw in my concept. Thanks for all the help.