Answer: Hi, so the travel starts at 6:00 am, and ends at 11:00 pm, this is a difference of 17 hours of travel. And we know that there where 3 hours (in the 4 breaks) + 2 hours (when visiting their friends) in which the Smiths where stop.
So the amount of hours in "motion" is : 17 hours - 5 hours = 12 hours.
now we know how much time they're actually traveling, and knowing the average velocity we can multiply the velocity by the time and obtain the miles traveled.
this is: 65m/h *12h = 780 miles.
so in their trip, the smiths travelled 780 milles.