this is pre calc arithmetic sequence. AT sea lvl pressure is 14.7 psi. It increases by 14.7 at every 30 ft descent. What is pressure at 1000 ft.
p = pressure
d = depth
p = 14.7 + 14.7 ( d / 30 ) =
14.7 ( 1 + d / 30 )
In this case d = 1000 ft
p = 14.7 ( 1 + 1000 / 30 ) =
14.7 ( 1 + 33.33 ) =
14.7 * 34.33 = 504.7 psi