If 30 grams of salt is dissolved in 120 grams of water, what is the salt content of the salt water?
30克盐溶解于120克水中，则这些盐水的含盐率是多少．
<gadget id="calculator">30 + 120</gadget>
<output>150</output>

<gadget id="calculator">30 / 150</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(1/5) * 1</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>