A typical scuba diving tank is initially filled with pressurized air at 3000in2. A good diver constantly
monitors the air tank pressure during a dive.
(a) [10 points] Suppose Cherie is using air at a rate of 42 lb per minute. Assuming she should
surface when her air pressure reaches 800in2, how long can she remain underwater?
(b) [10 points] Dave plans a dive that will require 80 minutes of underwater time. Assume he
lb
plans to surface when his air pressure reaches 200in2. What is the maximum rate at which
Dave can use his air, in units of
lb per minute.
Once you have converted lb to in^2,
(a) Solve for x in
3000 - 42x = 800
(b) Solve for r in
3000 - 80r = 200