1. The problem statement, all variables and given/known data At the surface of a freshwater lake the pressure is 106 kPa. (a) What is the pressure increase in going 34.5 m below the surface? (b) What is the approximate pressure decrease in going 36 m above the surface? Air at 20°C has density of 1.2 kg/m3. 2. Relevant equations Ph20 = pgh Pabs = Ph20 + Patm 3. The attempt at a solution I calculated both equations and got 439.4 kPa. I then subtracted 106 from 439.4 to get number one, but it doesn't work! How can I calculate number one? Also, I dont know where to begin for 2!