The three test tubes A, B, and C respectively contain 10 grams, 20 grams, and 30 grams of water. Pour 10 grams of a certain concentration of saline into test tube A, mix and pour 10 grams into test tube B, and mix them again. Take 10 grams from test tube B and pour it into test tube C. Now the concentration of saline in test tube C is 1%. What is the concentration of saline that was first poured into test tube A?
A、B、C三个试管中分别盛有10克、20克、30克水，把某种浓度的盐水10克倒人试管A中，混合后取出10克倒人试管B中，混合后又从试管B中取出10克倒人试管C中，现在试管C中盐水浓度是1%，最早倒人试管A中的盐水浓度是多少？
<gadget id="calculator">1 / 100</gadget>
<output>1/100 = around 0.01</output>

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

<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<gadget id="calculator">(1/100) * 4</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">10 + 20</gadget>
<output>30</output>

<gadget id="calculator">30 / 10</gadget>
<output>3</output>

<gadget id="calculator">(1/25) * 3</gadget>
<output>3/25 = around 0.12</output>

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

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

<gadget id="calculator">(3/25) * 2</gadget>
<output>6/25 = around 0.24</output>

<result>6/25 = around 0.24</result>