In the water tank, there are 2 kg of 13% salt water. Pour 600 grams and 300 grams of A and B salt water into the water tank respectively, and the salt water in the water tank becomes 10% salt water. up. If the concentration of salt B is twice that of salt A, what is the concentration of salt A?
在水槽里，装有13%的食盐水2千克，往这个水槽里分别倒入重600克和300克的A、B两种食盐水，水槽里的食盐水就变成了10%的食盐水了．B种食盐水浓度是A种食盐水浓度的2倍，则A种食盐水的浓度是多少．
<gadget id="calculator">2 * 1_000</gadget>
<output>2_000</output>

<gadget id="calculator">2_000 + 600 + 300</gadget>
<output>2_900</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">2_900 * (1/10)</gadget>
<output>290</output>

<gadget id="calculator">13 / 100</gadget>
<output>13/100 = around 0.13</output>

<gadget id="calculator">2_000 * (13/100)</gadget>
<output>260</output>

<gadget id="calculator">290 - 260</gadget>
<output>30</output>

<gadget id="calculator">30 / 600 / 2</gadget>
<output>1/40 = around 0.025</output>

<result>1/40 = around 0.025</result>