Answer: -3 degrees per hour.
Step-by-step explanation:
Given: The temperature fell from 0 degrees to \(6\frac{3}{5}\) degrees below 0 in \(2\frac{1}{5}\) hours.
The change in temperature=\(0-6\frac{3}{5}\)
\(=-\frac{33}{5}\) degrees
Time taken to change the temperature=\(2\frac{1}{5}=\frac{11}{5}\) hours
Now, the temperature change per hour is given by :-
\(\frac{\text{Change in temperature}}{\text{Time}}=\frac{-\frac{33}{5}}{\frac{11}{5}}\\\\=\frac{-33\times5}{11\times5}=-3\text{ degrees per hour}\)
