The salt content of a glass of salt water is 20%. If 10 grams of salt are added, the salt content becomes 25%. How many grams does this glass of salt water contain?
一杯盐水含盐率是20%，加入10克盐，含盐率变为25%，这杯盐水原来有多少克？
<gadget id="calculator">10 - 2.5</gadget>
<output>7.5</output>

<gadget id="calculator">0.25 - 0.2</gadget>
<output>0.05</output>

<gadget id="calculator">7.5 / 0.05</gadget>
<output>150</output>

<result>150</result>