A diver, when submerged in sea waters, suffers from increased pressure as he sinks. The pressure increase is described by a graph that passes through points (0, 2) and (20, 4), in atmosphere, as a function of depth, in meters. With this, determine the equation that expresses the pressure, in atmosphere, as a function of depth, in meters. And check what is the pressure suffered by the diver at 22 m depth?