Se da: m,s1=200g c1=5% c= m,dx100/ms
Pentru a concentra sol ,se adauga md substanta ; m,d se adauga si la m,d1 si m,s1
Calc md1: 5/100= m,d1/200---->m,d1=10g
Deci , in sol2 avem md2= md1+ md=10+md
ms2=200 + md--->20/100=(10+md)/(200+md)=>md=37,5g
md2= md1+md= 10+37,5
ms2= ms1+md=200+37,5