To calculate the time required to travel 1,400 miles at an average speed of 50 miles per hour, you can use the formula:
\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]
Plugging in the values:
\[ \text{Time} = \frac{1400 \text{ miles}}{50 \text{ miles per hour}} = 28 \text{ hours} \]
So, you must drive for 28 hours to make the trip from Poughkeepsie, New York, to West Palm Beach, Florida.