Final answer:
The question about the Smiths' beach trip does not provide enough information to calculate average speed, as the total distance and time are not given. To calculate average speed, one would use the formula Average Speed = Total Distance / Total Time, which isn't applicable here due to the lack of necessary data.
Step-by-step explanation:
To calculate the average speed of the Smiths during their beach trip, you need to know the total distance traveled and the total time taken for the trip. However, this information is not provided in the details you've given. As a reference, the average speed of a train mentioned travels 40 miles one way and 40 miles back, making a total distance of 80 miles. If we had the time it took for the train to travel this distance, we could calculate the average speed using the formula:
Average Speed = Total Distance / Total Time
Since the question about the Smiths' beach trip does not include enough information to answer it, we can't apply the same technique. We would need to know both the distance they traveled to the beach and the time it took. Therefore, I'm unable to provide the average speed for the Smiths' beach trip.