There are 180 grams of brine with a concentration of 2% in container A, and several grams of brine with a concentration of 9% in container B. Take 240 grams of brine from B and pour it into A, and then pour water into B. There are exactly the same amount in the two containers salt water of the same concentration. What is the concentration of the brine in the two containers at this time?
甲容器有浓度为2%的盐水180克，乙容器中有浓度为9%盐水若干克，从乙中取出240克盐水倒入甲，再往乙倒入水，两个容器中恰好有一样多同样浓度的盐水．此时两容器的盐水浓度为多少．
<gadget id="calculator">2 / 100</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">180 * (1/50)</gadget>
<output>18/5 = around 3.6</output>

<gadget id="calculator">9 / 100</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">240 * (9/100)</gadget>
<output>108/5 = around 21.6</output>

<gadget id="calculator">(18/5) + (108/5)</gadget>
<output>126/5 = around 25.2</output>

<gadget id="calculator">180 + 240</gadget>
<output>420</output>

<gadget id="calculator">(126/5) / 420</gadget>
<output>3/50 = around 0.06</output>

<result>3/50 = around 0.06</result>