If a product is sold at 25% off the list price and still earns a 5% profit, what is the expected profit margin when pricing it?
某种商品按定价打七五折销售，仍能获得5%的利润，定价时期望的利润率是多少？
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 + (1/20)</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(21/20) / (3/4)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">1 * (7/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">(7/5) - 1</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>