Question 215291
Let  x=  amt  of  added  solution
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.2x + .6*20 = .36(20+x) = 7.2 + .36x
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4.8 = .16x
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30 = x,,,,,in  liters
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check,,.2(30) + .6(20) = .36(50) = 6+12 = 18,,,,,,ok
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