Masa amestec m1+m2+m3 = 3m (m1=m2=m3 = m)
Vol. amestec m/ρ1 + m/ρ2 + m/ρ3 = m(ρ2ρ3+ρ1ρ3+ρ1ρ2) / ρ1ρ2ρ3
ρ = M/V; ρ = 3m : m( )/ρ1ρ2ρ3 = 3 × ρ1ρ2ρ3 : ( )
ρ = 3 x 0,8kg/dm³ x 0,9kg/dm³ x 1Kg/dm³ : ( 0,9·1 + 0,8·1 + 0,9·0,8) = 3 x 0,72 : 2,42 = 2,16 : 2,42 = 0,89256 kg/dm³
Masa a 3 litri (dm³) de amestec va fi 3dm³ x 0,893kg/dm³ = 2,679 kg