A velocity versus time graph shows the velocity in mph of a bicycle moving along a straight road

A velocity versus time graph shows the velocity in mph of a bicycle moving along a straight road. It has 3 distinct regions, one that is above the x-axis of area 10, one that is below the x-axis of area 15, and one that is above the x-axis of area 20.
Student #1 makes the statement, "Well, since area is always positive, that person traveled 10 +15+20 miles, so 45 miles total."
Student #2 claims: "No, that's all wrong, since 15 of it is negative, you've got 10 minus 15 plus 20 which is a total of 15 miles traveled." 
One of these students is correct.  Explain which one is correct and why.
The other student is correct, but to a different question. What would be a question to which to other student answered correctly?