<PRE><B>Question 821424</B>
A 4-liter container contains a mixture with a concentration of 50%. How much of this mixture must be withdrawn and replaced by 100% concentration to bring the mixture up to 75% concentration?
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Equation:
active - active + active = active
0.50*4 - 0.50x + 1*x = 0.75*4
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50*4 - 50x + 100x = 75*4
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50x = 25*4
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x = 2 liters (amt. of mixture to be removed and replaced.
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Cheers,
Stan H.
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