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 75 percent carbonated water, what percent of the volume of the mixture is P?
Choose the correct choice.
A) 40% B) 50% C) 60% D) 80% E) 90%
75% is 5%-points below 80% and 20%-points above 55%.   So the ratio of solution P to solution Q is 4:1.   Mixture P is 4/5 = 80% of the volume of mixture PQ.   The answer is 80%.
<result>D</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 75 percent carbonated water, what percent of the volume of the mixture is P?