The container that contains a greater volume of water will contain a greater mass of water.
The volume of the cube is given by:
V = s³
V = volume, s = side length
Given values:
s = 3m
Plug in and solve for V:
V = 3³
V = 27m³
The volume of the sphere is given by:
V = 4πr³/3
V = volume, r = radius
Given values:
r = 3m
Plug in and solve for V:
V = 4π3³/3
V = 113m³
The sphere contains more mass.