(a) When immersed in the liquid, the solid displaces an amount of liquid weighing 64 N - 48 N = 16 N, and this is the same as the magnitude of the buoyant force/upthrust.
(b) Archimedes' principle says the solid has a volume equal to that of the displaced liquid. At a density of 0.8 g/cm³ = 0.0008 kg/cm³, a 16-N amount of this liquid has a volume of
(16 N) / <em>g</em> × (1/0.0008 cm³/kg) = 2040.82 cm³
(c) Density is mass per unit volume, so you get the solid's density by dividing its mass (weight/<em>g</em>) by the volume in (b):
((64 N) / <em>g</em>) / (2040.82 cm³) ≈ 0.0032 kg/cm³ ≈ 3.2 g/cm³
