Question 319038
Let A be the volume of 10% solution.
Let B be the volume of 16% solution.
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The chemist has to produce 30 liters.
1.{{{A+B=30}}}
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The concentration of the 30 liters must be 14%.
{{{10A+16B=14(30)}}}
{{{10A+16B=420}}}
2.{{{5A+8B=210}}}
From eq. 1,
{{{A=30-B}}}
Substitute into eq. 2 and solve for B,
{{{5(30-B)+8B=210}}}
{{{150-5B+8B=210}}}
{{{150+3B=210}}}
{{{3B=60}}}
{{{highlight( B=20)}}}
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Now go back to the previous equation,
{{{A=30-B}}}
{{{A=30-20}}}
{{{highlight(A=10)}}}
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Use 10 liters of 10% solution and 20 liters of 16% solution to get 30 liters of 14% solution.