Add 10 kilograms of water to 20% saline salt water, and it will become 16% saline salt water. How many kilograms are there in the original salt water?
在含盐20%的盐水中，加入10千克水，就变成含盐16%的盐水，原来的盐水有多少千克？
<gadget id="calculator">0.2 - 0.16</gadget>
<output>0.04</output>

<gadget id="calculator">1.6 / 0.04</gadget>
<output>40</output>

<result>40</result>