Explanation:
Density is mass divided by volume. For example, Block A:
ρ = m / V
ρ = 60 g / 125 cm³
ρ = 0.48 g/cm³
I assume each block is a cube, so the length of block underwater divided by the side length of the block is the percent underwater.
% = 1.8 / 3.9
% = 46%
Repeat for Blocks B through E.
