Question 356356
Let {{{A}}} be the amount of 12% solution, {{{B}}} the amount of 22% solution.
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Total volume equation:
1.{{{A+B=120}}}
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Concentration equation:
{{{12A+22B=16(120)}}}
2.{{{6A+11B=960}}}
Multiply eq. 1 by (-6) and add to eq. 2 to eliminate A and solve for B.
{{{-6A-6B+6A+11B=-720+960}}}
{{{5B=240}}}
{{{highlight(B=48)}}}gallons
Then from eq. 1,
{{{A+48=120}}}
{{{highlight(A=72)}}}gallons