1. The problem statement, all variables and given/known data 2. Relevant equations dp/dz=-ρg p=ρgh 3. The attempt at a solution I've found the density at depth 3m using ρ=ρ0+kh, which gave me 1060kgm-3. I then put this value into ρgh to get 31195.8Pa which seems to be ≈+1000 off the answer. What is the correct mathematical way of solving this as I am not quite sure how to form the equation for variation of pressure using that.