Answer:
[tex]-4\ \text{feet/hour}[/tex]
Step-by-step explanation:
Level of water at 4 PM is 10 feet.
Level of water at 8 PM is 2 feet.
Time duration in which water level is measured is [tex]8-4=4\ \text{hours}[/tex]
The change of the level of water in the given time duration is [tex]2-10=-8\ \text{feet}[/tex]
The rate of change would be
[tex]R=\dfrac{-8}{4}=-4\ \text{feet/hour}[/tex]
The constant rate of change of the water is [tex]-4\ \text{feet/hour}[/tex].
The minus sign indicates that the water level is reducing.