Answer:
30 miles.
Explanation:
A van will drive 10 miles north, 15 miles south, and then 5 miles north again.
Van will drive total distance = 10 + 15 + 5 = 30 miles.
Relative distance is 0 miles since the van is back where it started.
The total distance to travel is 30 miles and van gets 33 miles per gallon. There is one gallon of gas left in the tank so there is enough fuel for the trip.