There are several ways to solve it.


One way is to solve the system of 2 equations

       x +     y = 3.2     for the total volume of two solutions (in liters)   (1)

  0.047x + 0.19y = 0.086*3.2   for the mass of salt (in kilograms)             (2)


You may use the Elimination method. For it, multiply eq(1) by 0.047 (both sides). Keep eq(2) as is. You will get


   0.047x + 0.047y = 0.047*3.2    (3)

   0.047x + 0.19y  = 0.086*3.2    (4)    ( same as (2) )


Now subtract eq(3) from eq(4). You will get


            (0.19y - 0.047y) = 0.086*3.2 - 0.047*3.2


which gives you  y =  .


Now I copy this formula in MS Excel in my computer and get the answer in one click:  y = 0.873.


Then from eq(1),  x = 3.2 - 0.873 = 2.327.


Answer.  2.327 liters of the 4.7% solution and  0.873 liters of the 19% solution.