Answer: B. The Total profit made when a person buys a car for $10,000 and sells it for $10,000.
Step-by-step explanation:
Answer A would be wrong since when there is a temperature change from 15 degrees to -15 degrees would lead to an overall change of 30 degrees.
Answer C would be wrong as well since it is decreasing 500 feet in altitude, meaning that there is a negative change in altitude.
Answer D would also be wrong since the train is traveling 35 miles north, then south. That means that even though the train is in the same place that is was before, it traveled a total of 70 miles to return to where it was previously at.
Hope this helps!