Solution P is 20 percent lemonade and 80 percent carbonated water by volume; solution Q is 45 percent lemonade and 55 percent carbonated water by volume. If a mixture of PQ contains 67.5% percent carbonated water, what percent of the volume of the mixture is P?	Choose the correct choice:
A) 25%	B) 40%	C) 50%	D) 60%	E) 75%
67.5% is 12.5%-points below 80% and 12.5%-points above 55%.   So the ratio of solution P to solution Q is 1:1.   Mixture P is 1/2 = 50% of the volume of mixture PQ.   The answer is 50%.
<result>C</result>
Solution P is 20 percent lemonade and 80 percent carbonated water by volume; solution Q is 45 percent lemonade and 55 percent carbonated water by volume. If a mixture of PQ contains 67.5% percent carbonated water, what percent of the volume of the mixture is P?