The two cups are filled with 40% and 10% salt water respectively, and the concentration of the salt water becomes 30% after being poured together and mixed. If 600 grams of 20% salt water is added, the concentration becomes 25% after mixing, then How much is the original 10% salt water in grams?
两个杯子中分别装有浓度为40%与10%的盐水，倒在一起混合后盐水的浓度变为30%，若再加人600克20%的盐水，混合后浓度变为25%，那么原有10%的盐水多少克．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(3/10) - (1/10)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) - (3/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/5) / (1/10)</gadget>
<output>2</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">600 * (1/3)</gadget>
<output>200</output>

<result>200</result>