Add 40 kg of salt to 600 kg of brine containing 20% salt, find the current salt content.
在600千克含盐20%的盐水中加入40千克的盐，求现在的含盐率．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">600 * (1/5)</gadget>
<output>120</output>

<gadget id="calculator">120 + 40</gadget>
<output>160</output>

<gadget id="calculator">600 + 40</gadget>
<output>640</output>

<gadget id="calculator">160 / 640</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/4) * 1</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>