Question

the temperature dropped by 7.f each hour from 5:00 am to 9:00 am. What was the beginning temperature at 5:00 am if the temperature at 9:00 am was -10.f

Answer 1

4 * 7 = 28.
28 + (-10) = 18
Therefore, the answer is 18.

If you want to check this, you can subtract 7 from 18 four times.