Pressure against the depth

How does the pressure grow as a diver goes down, in a lake and in the sea? You will make the program find the absolute pressure at every depth down to $50\ \text{m}$ in fresh water and in sea water, and the depth at which the sea's pressure is three atmospheres.

The idea. $p = p_0 + \rho gh$, with $p_0 = 1.013 \times 10^{5}\ \text{Pa}$, $\rho = 1000\ \text{kg/m}^3$ for fresh water and $1030$ for the sea.

Your tasks.

1. Work out p_fresh, the absolute pressure at every depth in fresh water.
2. Work out p_sea, the same in sea water.
3. Find the depth at which the pressure in the sea is three atmospheres.