The original price of a product is 450 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450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">450 * (7/10)</gadget>
<output>315</output>

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

<gadget id="calculator">450 * (9/10)</gadget>
<output>405</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">405 / (27/20)</gadget>
<output>300</output>

<gadget id="calculator">315 - 300</gadget>
<output>15</output>

<gadget id="calculator">15 / 300</gadget>
<output>1/20 = around 0.05</output>

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