<PRE><B>Question 1028678</B>
You need a 55% alcohol solution. On hand, you have a 375 mL of a 50% alcohol mixture. You also have 80% alcohol mixture. How much of the 80% mixture will you need to add to obtain the desired solution? 
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Equation:
alco + alco = alco
0.50*375 + 0.80x = 0.55(375+x)
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50*375 + 80x = 55*375 + 55x
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25x = 5*375
x = 375/b = 75 mL (amt. of 80% needed)
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Cheers,
Stan H.
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