A shopping mall prices a commodity at 390 yuan after adding 50% of the purchase price. How much is the purchase price of this commodity?
某商场将一种商品按进价的50%加价后定价为390元，这种商品的进价是多少元？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">390 / (3/2)</gadget>
<output>260</output>

<result>260</result>