Answer:
The answer is 15 ft.
Step-by-step explanation:
I hope this helps
Answer:
32 Liters
Step-by-step explanation:
In the glass tank:
W = represents the volume of water Andrei uses (in liters)
n =Number of marbles
Given that: 
The volume of the glass tank is the volume of the water in the tank plus the total volume of n marbles added.
Therefore:

Volume of the tank =32 Liters
The surface of the water is 0 feet. So 10 feet down means it is 0 - 10, or -10 feet as its final position.
The greatest area he can fence is 64 ft².
In order to maximize area and minimize perimeter, we use dimensions that are as close to equivalent as possible. 32 feet of fence for 4 sides gives us 8 feet of fence per side. We would have a square whose side length is 8; the area would be 8*8 = 64.