35 liters of a mixture is created by mixing Liquid P and Liquid Q in the ratio 4:3. How many liters of Liquid Q must be added to make the ratio 5:7?  Choose one.
A) 10  B) 11  C) 12  D) 13  E) 14
Let x be the amount of liquid Q to be added.   (3/7)*35 + x = (7/12)*(35+x)   1260 + 84x = 1715 + 49x   35x = 455   x = 13   The answer is 13.
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35 liters of a mixture is created by mixing Liquid P and Liquid Q in the ratio 4:3. How many liters of Liquid Q must be added to make the ratio 5:7?