<PRE><B>Question 995551</B>
 Beau wishes to strengthen a mixture from 10% alcohol to 30% alcohol.How much pure alcohol should be added to 7 L of 10% mixture. 
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Equation:
alch + alch = alch
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0.10*7 + 1*x = 0.30(7+x)
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10*7 + 100x = 30*7 + 30x
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70x = 20*7
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x = 2 L (amt of pure alcohol to add)
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Cheers,
Stan H.
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