C₁=20%
C₂=36%
Cf=30%
ms₁=200g
Fie ms₂ masa solutiei de C₂.
Luam masele solutiilor ca ponderi si obtinem:
ma(media aritmetica)=(200x20+ms₂x36)/(200+ms₂)=30
(4000+36ms₂)/(200+ms₂)=30
4000+36ms₂=30x(200+ms₂)
4000+36ms₂=30x200+30xms₂
4000+36ms₂=6000+30ms₂
4000+36ms₂-30ms₂=6000
4000+6ms₂=6000
6ms₂=6000-4000
6ms₂=2000
ms₂=2000/6
ms₂≈333,33g
