In order to prevent colds in winter, the school doctor's office prepared a disinfectant at a ratio of 1:200. Now there are 2 bottles of 105ml liquid medicine, how many liters of water need to be added?
为了预防冬季感冒，校医室按1：200的配比配制了消毒液．现在有2瓶105毫升的药液，需要加入多少升水？
<gadget id="calculator">0.105 * 2</gadget>
<output>0.21</output>

<gadget id="calculator">1 / 200</gadget>
<output>1/200 = around 0.005</output>

<gadget id="calculator">0.21 / (1/200)</gadget>
<output>42</output>

<result>42</result>