The three test tubes A, B, and C each hold several kilograms of water. Now pour 10 grams of brine with a concentration of 12% into A. After mixing, take out 10 grams and pour them into B. After mixing, take out 10 grams and pour them into C. The result is A. The concentration of the three test tubes , B, and C are 6%, 2%, and 0.5% respectively. How many grams of water is contained in the three test tubes that hold the most water?
A、B、C三试管各盛水若千克，现将浓度12%的盐水10克倒入A中，混合后取出10克倒入B中，混合后再取出10克倒入C中，结果A、B、C三试管浓度分别为6%、2%、0.5%三试管中原盛水最多的盛了多少克水？
<gadget id="calculator">12 / 100</gadget>
<output>3/25 = around 0.12</output>

<gadget id="calculator">6 / 100</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">(3/25) / (3/50)</gadget>
<output>2</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">20 - 10</gadget>
<output>10</output>

<gadget id="calculator">40 - 10</gadget>
<output>30</output>

<result>30</result>