so at sea lvl pressure is 14.7. EVERY 30 FT DESCENT ITS INCREASES BY 14.7 PSI MORE. what is the pressure at 1000ft. my question is what would be the first term 14.7 or 29.4. AS 14.7 would be the 0 term. term 1 would be 29.4 as its 30 ft below. sea lvl would be at zero right, but my textbook says the other way around, so who's correct me or my textbook.

Question

Steve · Answer

This isn't really an arithmetic series problem. It's a linear function, where the slope is 14.7/30

At x feet, the pressure p is

p(x) = 14.7 + (x/30)(14.7) =

so, at 1000ft, P = 14.7 + (1000/30)(14.7) = 504.7 psi

ISOSMEXY · Answer

Steve thanks, but this could be solved as a arithmetic sequence problem if you do 29.4+(33.3333333-1)x14.7= which gives us 504.7 as well. It seems my textbook is wrong so that's good. Also thanks for your help! :)