d-= m/v m = dxv = 0,7 x 80 = 56 grame solutie 62% alcool
c / 100 = masa dizolvata /m solutie ===> md = c x ms : 100 = 62 x 56/100= 34.72 grame alcool
20/100 = md / ms ms = md x 100 /20 = 34,72 x 5 = 173,6 grame solutie
173, 6 - 56 = 117,6 grame apa = 117, 6 cm cubi de apa = 117,6 ml