One fourth of a solution that was 10% sugar by weight was replaced by a second solution resulting in a solution that was 20 percent sugar by weight. The second solution was what percent sugar by weight? Pick.
A) 65% B) 50% C) 22% D) 18% E) 8.5%
Say the second solution (which was 1/4 th of total) was x% sugar, then 3/4*0.1+1/4*x=1*0.20 --&gt; x=0.5. Alternately you can consider total solution to be 100 liters and in this case you'll have: 75*0.1+25*x=100*0.20 --&gt; x=0.5.   Answer: 50%.
<result>B</result>
One fourth of a solution that was 10% sugar by weight was replaced by a second solution resulting in a solution that was 20 percent sugar by weight. The second solution was what percent sugar by weight?