A commodity is priced at a 20% profit, and then sold at a 15% discount, the profit is 140 yuan. What is the purchase price of this item?
某商品按20%的利润来定价，然后按八五折出售，可获得利润140元．则这件商品的进价是多少元．
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * (17/20)</gadget>
<output>17/100 = around 0.17</output>

<gadget id="calculator">(17/100) - 1</gadget>
<output>-83/100 = around -0.83</output>

<gadget id="calculator">(17/20) + (-83/100)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">140 / (1/50)</gadget>
<output>7_000</output>

<result>7_000</result>