Answer:
-21/8 or -2 5/8
Step-by-step explanation:
The lake change is the same for all 7 years so you can subtract -3/8 seven times.
-3/8-3/8-3/8-3/8-3/8-3/8-3/8 = -21/8
as a mixed number it's -2 5/8
It would 6 Pounds/ Liquid gallon.
Not enough info for a valid answer.