Given:
3 liter of a 40% alcohol solution.
[tex]\begin{gathered} =3\times\frac{40}{100} \\ =3\times0.4 \\ =1.2 \end{gathered}[/tex]Then here 1.2 liter of alcohol.
3 liter of a 75% alcohol solution.
[tex]\begin{gathered} =3\times\frac{75}{100} \\ =2.25 \end{gathered}[/tex]So 2.25 liter pure alcohol required in 3 liter of solution.
for add 2.25 liter alcohol solution
[tex]\begin{gathered} =2.25-1.2 \\ =1.05 \end{gathered}[/tex]So the 1.05 liter alochol required to maintain the 75% alcohol solution.
