bottle of 600 grams of sugar water contains 60 grams of sugar. After drinking 50 grams, add 50 grams of water. In order to make the concentration of the sugar water the same as before, how many grams of sugar must be added.
一瓶600克的糖水中含糖60克，喝掉50克后又加入50克水，为了使糖水的浓度和原来一样，必须加入多少克糖．
<gadget id="calculator">60 * 50</gadget>
<output>3_000</output>

<gadget id="calculator">600 - 60</gadget>
<output>540</output>

<gadget id="calculator">3_000 / 540</gadget>
<output>50/9 = around 5.555556</output>

<result>50/9 = around 5.555556</result>