The temperature at 09:00 was - 3°C. Over the next 6 h, the temperature dropped 2°C, rose 3°C, rose 2°C, dropped 1°C, rose 4°C, and dropped 2°C. What was the temperature at 15:00?

1°C

Step-by-step explanation:

The inicial temperature at 09:00 was - 3°C.

The changes in temperature in each of the six hours were:

first hour: - 2°C

secondhour: + 3°C

third hour: + 2°C

fourth hour: - 1°C

fifth hour: + 4°C

sixth hour: - 2°C

So, the temperature at 15:00 is the sum of the inicial temperature and all of these changes:

Temperature at 15:00 = - 3°C - 2°C + 3°C + 2°C - 1°C + 4°C - 2°C = 1°C