340. A scientist pours 20 liters of a 16% alcohol solution i

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340. A scientist pours 20 liters of a 16% alcohol solution into 60 liters of a 20% alcohol solution. How many liters of the resulting solution must she add to 10 liters of a 30% alcohol solution to create a solution that is 24% alcohol?
A. 23 liters
B. 13 liters
C. 15 liters
D. 12 liters
E. 20 liters
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by puneetkhurana2000 » Sun Dec 16, 2012 2:00 pm
Resulting solution is (20*16 + 60*20)/(20+60) = 19% alcohol.

Now using mixture formulas, we get (30-24)/(24-19) = (x/10) , solving we get x = 12 liters.

Answer D.