Answer :
Let the amount of gallons of 10% solution be "x", and
Let the amount of gallons of 60% solution be "y".
We need 150 gallons, thus we can write:
[tex]x+y=150_{}[/tex]Both 10% and 60% solution needs to be mixed to produce 150 gallons of 50% solution. We can write:
[tex]\begin{gathered} 0.1x+0.6y=0.5\times150 \\ 0.1x+0.6y=75 \end{gathered}[/tex]Solving for "x" in the first equation >>>
[tex]\begin{gathered} x+y=150 \\ x=150-y \end{gathered}[/tex]We will substitute it into the second equation and solve for "y" >>>
[tex]\begin{gathered} 0.1x+0.6y=75 \\ 0.1(150-y)+0.6y=75 \\ 15-0.1y+0.6y=75 \\ 0.5y=60 \\ y=120 \end{gathered}[/tex]Now, we can solve for "x" using the first equation >>>>
[tex]\begin{gathered} x=150-y \\ x=150-120 \\ x=30 \end{gathered}[/tex]AnswerWe need 30 gallons of 10% solution and 120 gallons of 60% solution