30 liters of a mixture is created by mixing Liquid P and Liquid Q in the ratio 3:2. How many liters of Liquid Q must be added to make the ratio 3:4?  Choose the correct choice from the following answers
A) 8
B) 10
C) 12
D) 14
E) 16
Let x be the amount of liquid Q to be added.   (2/5)*30 + x = (4/7)*(30+x)   420 + 35x = 600 + 20x   15x = 180   x = 12   The answer is 12.
<result>C</result>
30 liters of a mixture is created by mixing Liquid P and Liquid Q in the ratio 3:2. How many liters of Liquid Q must be added to make the ratio 3:4?