Final answer:
The tank gauge reading of 200 psi indicates the gauge pressure of the nitrous oxide/oxygen tanks.
Step-by-step explanation:
The tank gauge reading of 200 psi indicates the gauge pressure of the nitrous oxide/oxygen tanks. Gauge pressure is the pressure relative to the atmospheric pressure.
When the gauge reads a positive value, it means the pressure inside the tank is greater than atmospheric pressure. In this case, a reading of 200 psi indicates that the pressure in the tank is 200 psi higher than atmospheric pressure.