salt water, the mass ratio of salt to water is 7:20. Now there are 14 grams of salt, how many grams of water need to be added to prepare this brine.
一种盐水，盐与水的质量比是7：20．现在有14克盐，要配置这种盐水，需要加入水多少克．
<gadget id="calculator">20 * 14</gadget>
<output>280</output>

<gadget id="calculator">280 / 7</gadget>
<output>40</output>

<result>40</result>