Answer:
Greater than 31 feet.
Step-by-step explanation:
Let x be the water level before the cleaners took out any water.
Now, the water level decreased by 6 feet during cleaning.
Hence, the water level after cleaning is x -6
Now, it has been given that water level in the aquarium's shark tank is always greater than 25 feet
Thus, the inequality for the situation is
[tex]x-6>25[/tex]
Add 6 to both sides
[tex]x>25+6\\x>31[/tex]
Hence, the water level before the cleaners took out any water was greater than 31 feet.
