Final answer:
Superman took 20 hours to get to New York City.
Step-by-step explanation:
To calculate the time it took Superman to fly from San Francisco to New York City, we can use the formula:
Time = Distance / Speed
Given that the distance is 6000 kilometers and the speed is 300 km/hr, we can substitute these values into the formula:
Time = 6000 km / 300 km/hr = 20 hrs
Therefore, it took Superman 20 hours to get to New York.