In order to find if the cube will float or sink, first let's calculate the volume of the cube.
The volume of a cube is given by the side length to the power of 3:
![\begin{gathered} V=s^3 \\ V=6^3 \\ V=216\text{ cm^^b3} \end{gathered}]()
Now, let's calculate the density of the cube:
![d=(m)/(V)=(140)/(216)=0.648\text{ g/cm^^b3}]()
The density of water is 1 g/cm³. Since the density of the cube is lesser than the density of the water, therefore the cube will float.