A team of engineers is trying to pump out the air in a vacuum chamber to lower the pressure. They know that the following equation represents the pressure in the chamber:
$$
P=35-0.07 s
$$
where $P$ is the pressure in pounds per square inch (psi) of the vacuum chamber and $s$ is the time in seconds.
a. What will the pressure be after 150 seconds?
b. When will the pressure inside the chamber be 1 psi?