Answer:
2 meters.
Step-by-step explanation:
We know that a cube of sidelength L has a volume:
V = L^3
Here, we know that the volume of water that the cube can hold is:
(1000/125) m^3
Then the volume of our cube is exactly that:
V = (1000/125) m^3
Then we have the equation:
L^3 = (1000/125) m^3
Which we can solve for L
L = ∛((1000/125) m^3 ) = (∛1000/∛125) m
Where we used that:
∛(a/b) = ∛a/∛b
Solving the cubic roots, we get:
L = (10/5) m = 2m
The length of the side of the water tank is 2 meters.