Based on the graph you've provided, it shows Zane's elevation over time as he climbs out of the volcano. The line on the graph represents his path, and the coordinates you've mentioned, (35, 0) and (0, -25), provide us with information on his climb.
The point (35, 0) indicates that at 35 seconds, Zane reached the edge of the volcano, as his elevation relative to the edge is 0 meters. The point (0, -25) suggests that at the beginning of the observation (time 0 seconds), Zane was 25 meters below the edge of the volcano.
Therefore, it took Zane 35 seconds to reach the edge of the volcano from the time he started. There is no calculation needed as the time is directly given by the x-coordinate of the point where the line intersects the x-axis (time axis) at an elevation (y-coordinate) of 0 meters.