Final answer:
The normal reading of the red hand of the duplex air gauge should be approximately 25 pounds.
Step-by-step explanation:
The normal reading of the red hand of the duplex air gauge should be approximately 25 pounds.
Gauges measure pressure, which is converted into a readout. In this case, the air pressure is measured in pounds per square inch (psi). The normal reading of the red hand on the air gauge falls within the range of 18-99 pounds.