1. The problem statement, all variables and given/known data One hundred millilitres of water is poured into a U-tube that has a cross-sectional area of 1 cm2. Then 100 millilitres of oil, with a density 80% that of water, is poured down one side of the U-tube so that the oil floats on the water. Find the difference in height of the liquid surfaces on the two sides of the U-tube. 2. Relevant equations P=gph 3. The attempt at a solution Just struggling to get started, i know that on either side that at a certain point the pressures are equal. Just a pointer to get going would be great..