An individual clothing dealer cuts the original price of a piece of clothing by 15% twice in a row for a clearance sale. At this time, the price is 289 yuan. It is known that the purchase price of this piece of clothing is 70% of the original price. How much is the purchase price of this piece of clothing? ?
某个体服装商清仓甩卖，将一件衣服的原标价连续两次降15%，这时的标价为289元，已知这件衣服进价是原标价的70%，这件衣服进价多少元？
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 - (3/20)</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">(17/20) * (17/20)</gadget>
<output>289/400 = around 0.7225</output>

<gadget id="calculator">289 / (289/400)</gadget>
<output>400</output>

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

<gadget id="calculator">400 * (7/10)</gadget>
<output>280</output>

<result>280</result>