The original price of a commodity is 540 yuan, and the profit margin is 35% when it is sold at a 10% discount; if it is sold at a 30% discount, what is the profit margin?
一件商品的原价540元，打九折售出时利润率是35%；如果打七折售出，利润率是多少．
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">540 * (7/10)</gadget>
<output>378</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">540 * (9/10)</gadget>
<output>486</output>

<gadget id="calculator">35 / 100</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">1 + (7/20)</gadget>
<output>27/20 = around 1.35</output>

<gadget id="calculator">486 / (27/20)</gadget>
<output>360</output>

<gadget id="calculator">378 - 360</gadget>
<output>18</output>

<gadget id="calculator">18 / 360</gadget>
<output>1/20 = around 0.05</output>

<result>1/20 = around 0.05</result>