Solution:
Let "x" be the liters of 20 % solution
Then, (80 - x) is the liters of 60 % solution
Final mixture is 80 liters of 30 % solution
Therefore,
"x" liters of 20 % solution and 80 - x liters of 60 % solution is mixed to get 80 liters of 30 % solution
Thus a equation is framed as:
[tex]20 \% \times x + 60 \% \times (80-x) = 30 \% \times 80\\\\\frac{20}{100} \times x + \frac{60}{100} \times (80-x) = \frac{30}{100} \times 80\\\\0.2x + 0.6(80-x) = 24\\\\0.2x + 48 - 0.6x = 24\\\\0.4x = 24\\\\x = 60[/tex]
Thus, 60 liters of 20 % solution
Then, (80 - x) = 80 - 60 = 20
20 liters of 60 % solution