Final answer:
The maximum number of 125V, 20A, general-purpose duplex receptacles allowed on a 20A, 120V, circuit in a commercial building is 1.
Step-by-step explanation:
The maximum number of 125V, 20A, general-purpose duplex receptacles allowed on a 20A, 120V, circuit in a commercial building is determined by the circuit capacity and safety regulations. Safety regulations limit continuous use to 80% of the circuit breaker's current capacity, which means the maximum allowable continuous load on a 20A circuit is 16A (80% of 20A). Since each general-purpose duplex receptacle draws 20A, the maximum number of receptacles allowed on a 20A circuit is 1.