1. An airplane is flying high enough that the cabin pressure is 7.4 lb/in2. In the absence of any supplemental oxygen, what is the partial pressure of oxygen in the cabin? Assume sea level pressure is 14.7 lb/in2 and that the percentage of oxygen in the air is 21%. State your answer rounded to the nearest hundredth of a lb/in2.
2. The background sound level at your plant is 82.5 dBA. If a compressor generates a sound level of 87.2 dBA, what will the combined sound level be when the compressor is on? (State your answer to the nearest tenth of a dBA)