Sure, let's address this question step by step based on the given information.
First, we note the elevations at various points in time for both Melissa and Corey. From the table:
| Time (min) | Melissa | Corey |
|------------|---------|--------|
| 0 | 8,342 | 10,004 |
| 30 | 9,550 | 11,432 |
| 60 | 11,239 | 12,921 |
| 90 | 12,921 | 11,075 |
| 120 | 12,921 | 10,004 |
We are given that Melissa and Corey crossed paths between 60 and 90 minutes. Let's carefully analyze the changes in their elevations during this period.
### Elevation Difference at the Start of the Crossing (60 minutes)
At 60 minutes:
- Melissa's elevation is 11,239 feet.
- Corey's elevation is 12,921 feet.
The difference in their elevations at 60 minutes is:
[tex]\[ \text{Difference} = 11,239 - 12,921 = -1,682 \][/tex]
### Elevation Difference at the End of the Crossing (90 minutes)
At 90 minutes:
- Melissa's elevation is 12,921 feet.
- Corey's elevation is 11,075 feet.
The difference in their elevations at 90 minutes is:
[tex]\[ \text{Difference} = 12,921 - 11,075 = 1,846 \][/tex]
### Summary
- Melissa and Corey crossed paths between 60 and 90 minutes.
- At 60 minutes, the elevation difference was -1,682 feet (Melissa was 1,682 feet below Corey).
- At 90 minutes, the elevation difference was 1,846 feet (Melissa was 1,846 feet above Corey).
Thus, the key points from this analysis are:
- The time interval during which they crossed was from 60 minutes to 90 minutes.
- The elevation difference at the start of this interval was -1,682 feet.
- The elevation difference at the end of this interval was 1,846 feet.
