We know that
• Pure acid is added to a 5% acid solution.
,• To obtain 95 liters of 28% solution.
Based on the given information, we can define the following formula
[tex]x+0.05(95-x)=0.28\cdot95[/tex]Where 0.05 is 5% and 0.28 is 28%.
Solving for x, we have
[tex]\begin{gathered} x+4.75-0.05x=26.6 \\ 0.95x=26.6-4.75 \\ 0.95x=21.85 \\ x=\frac{21.85}{0.95}=23 \end{gathered}[/tex]Now, to find the liters of 100% pure acid, we use the following equation.
[tex]23+0.05\cdot72=0.28\cdot95=26.6[/tex]