To find out how much the air temperature changed each hour during the 10-hour storm, you need to divide the total change in temperature by the number of hours the storm lasted.
The total change in temperature is \(-3 \frac{3}{4}\) degrees. First, we need to convert \(-3 \frac{3}{4}\) into an improper fraction:
\[ -3 \frac{3}{4} = -\left(3 \times 4 + 3\right) / 4 = -\frac{15}{4} \text{ degrees} \]
Now, divide this by the number of hours (10):
\[ \text{Change per hour} = \frac{-\frac{15}{4}}{10} = -\frac{15}{4} \times \frac{1}{10} = -\frac{15}{40} = -\frac{3}{8} \]
Thus, the air temperature changed by \(-\frac{3}{8}\) degrees every hour.
So the final answer is:
The air temperature changed by \(-\frac{3}{8}\) degrees every hour.