Salad dressing P is made up of 30% vinegar and 70% oil, and salad dressing Q contains 10% vinegar and 90% oil. If the two dressings are combined to produce a salad dressing that is 12% vinegar, dressing P comprises what percentage of the new dressing?  Choose one
A) 50%
B) 40%
C) 30%
D) 20%
E) 10%
Let x be the percentage of dressing P in the new dressing.   0.3x + 0.1(1-x) = 0.12   0.2x = 0.02   x = 0.1 = 10%   The answer is 10%.
<result>E</result>
Salad dressing P is made up of 30% vinegar and 70% oil, and salad dressing Q contains 10% vinegar and 90% oil. If the two dressings are combined to produce a salad dressing that is 12% vinegar, dressing P comprises what percentage of the new dressing?