At 7:00 AM, the temperature started dropping 1 degree Celsius per hour until it reached 30 degrees Celsius at 12:00 PM. What was the temperature at 7:00 AM?
7:00 AM to 12:00 PM is 5 hours.
1 degree per hour * 5 hours = 5 degrees.
If it's 30 degrees at 12 pm, then it was 30 + 5 = 35 degrees...