A suit of a certain brand sells for 30% off and earns 80 yuan, and sells for 20% off and earns 100 yuan. What is the purchase price of this suit?
某品牌西服，打七折销售赔80元，打八折销售赚100元，这种西服的进价是多少元？
<gadget id="calculator">80 + 100</gadget>
<output>180</output>

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

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">(4/5) - (7/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">180 / (1/10)</gadget>
<output>1_800</output>

<result>1_800</result>