A piece of clothing is priced at 30% of the purchase price, and later sold at a 20% discount because of the warmer weather. At this time, you can only earn 20 yuan. How much is the purchase price of this clothing?
一件衣服按提高进价的30%定价，后来因天气变暖，打八折出售，这时只能赚20元，这件衣服的进价多少元？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 + (3/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(13/10) * (4/5)</gadget>
<output>26/25 = around 1.04</output>

<gadget id="calculator">(26/25) - 1</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">20 / (1/25)</gadget>
<output>500</output>

<result>500</result>