Question 318539
1.{{{A+B=300}}}
{{{50A+20B=40(300)}}}
{{{50A+20B=12000}}}
2.{{{5A+2B=1200}}}
Multiply eq. 1 by (-5) and add it to eq. 2,
{{{-5A-5B+5A+2B=-1500+1200}}}
{{{-3B=-300}}}
{{{highlight(B=100)}}}
Then from eq. 1,
{{{A+100=300}}}
{{{highlight(A=200)}}}
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200 liters of 50% solution and 100 liters of 20% solution.