If after 200 grams of water were added to the 15%-solution of alcohol, the strength of the solution decreased by one-third, how much of the 15%-solution was used? Choose the correct answer
A) 180 grams	B) 220 grams	C) 250 grams	D) 350 grams	E) 400 grams
The 15% alcohol solution decreases by 1/3 once the 200 grams of water is added so  200/.05= 
<gadget id="calculator"> 200/.05</gadget>
<output>4_000</output>
4000*.1% (2/3 of 15%) is 400 grams, thus answer is 400 grams.
<result>E</result>
If after 200 grams of water were added to the 15%-solution of alcohol, the strength of the solution decreased by one-third, how much of the 15%-solution was used?