Answer: 15,000 meters
Explanation:
When measuring the difference in elevations between a body that is above sea level and one that is below, you simply take the distances of the bodies above and below sea level and add it up.
From sea level to Mount Ojos is 6,900 meters. Atacama trench is 8,100 meters below. From the peak of Mount Ojos to sea level is 6,900 meters. Then add the distance from sea level to Atacama to find the difference in elevations.
= 6,900 + 8,100
= 15,000 meters