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