A portion of the 80% solution of chemicals was replaced with an equal amount of 20% solution of chemicals. As a result, 50% solution of chemicals resulted. What part of the original solution was replaced?  Choose the correct choice from the following:	A) 1/3	B) 1/2	C) 1/4	D) 1/5	E) 1/6
This is a weighted average question. Say x% of the solution was replaced --&gt; equate the amount of chemicals: 0.8(1-x)+0.2*x=0.5 --&gt; x=1/2.   Answer: 1/2.
<result>B</result>
A portion of the 80% solution of chemicals was replaced with an equal amount of 20% solution of chemicals. As a result, 50% solution of chemicals resulted. What part of the original solution was replaced?