To answer this question, we need to sum integers for each case. We also need to take into account that when a measure of a variable drops, we have a negative sign on it, and when a measure of the variable raises, we have a positive sign in this measure. Then, we need to evaluate each case:
1. Temperature was 10 degrees at 7:00 am. The temperature then rose 10 degrees from 7:00 am to 8:00 am. Then, we have:
10 + 10 = 20. Then, the temperature rose to 20 degrees.
2. We have:
Starting temperature: -5
Final temperature: dropped 5 degrees
Then, we have -5 - 5 = -10. The final temperature is -10 degrees.
3. We have:
Starting temperature: T1
The temperature drops 14, and then 14 again. Then, we have T1 - 14 - 14 ---> T1 - 28.
4. The temperature drops 15, and then rises 15. In this case, we have that the original temperature remains:
Starting temperature: T1
Then, we have T1 - 15 + 15 = T1 + 0. In this case, the sum of both temperatures is equal to zero.
5. For this case, we have:
Starting temperature: -3. Then, the temperature rose 3. Then, we have that the sum is equal to -3 + 3 = 0. In this case, the sum of both temperatures is equal to zero.
6. For this case, we have:
Starting temperature: 7 degrees. The temperature then drops 7 degrees. Then, we have:
7 - 7 = 0
In this case, the sum of both temperatures is equal to zero.
Therefore, the situations when we encounter a sum of 0 were in the Fourth, Fifth, and Sixth situations.